Why isn't my data not transferring between my two View Controllers using UITableViews?

I am attempting to pass data from a the UITableView function cellForRowAt to a custom UITableViewCell. The cell constructs a UIStackView with n amount of UIViews inside of it. n is a count of items in an array and is dependent on the data that is suppose to be transferred (a count of items in that array). Something very confusing happens to me here. I have checked in the VC with the tableView that the data has successfully passed by using the following snippet of code

print("SELECTED EXERCISES: ", self.selectedExercises)
cell.randomSelectedExercises = self.selectedExercises
print("PRINTING FROM CELL: ", cell.randomSelectedExercise)

I can confirm that both of these print statements return non-empty arrays. So to me, this means that the custom cell has the data I require it to have. But, when I try to print out the very same array in the UITableViewCell swift file (randomSelectedExercises) , it returns empty to me. How is this possible? From what I understand, the cell works on creating the property initializers first, then 'self' becomes available. I had a previous error telling me this and to fix it, I turned my UIStackView initializer to lazy, but this is how I ended up with my current problem.

Here is the code in beginning that is relevant to the question that pertains to the table view. I have decided to present this code incase the issue is not in my cell but in my table view code:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "RoutineTableViewCell") as! RoutineTableViewCell
        let workout = selectedWorkouts[indexPath.row]
        
        //get the information we need - just the name at this point
        let name = workout["name"] as! String
        
        
        var randomInts = [Int]()
        
        //perform a query
        
        let query = PFQuery(className: "Exercise")
        query.includeKey("associatedWorkout")
        //filter by associated workout
        query.whereKey("associatedWorkout", equalTo: workout)
        query.findObjectsInBackground{ (exercises, error) in
            if exercises != nil {

                //Created an array of random integers... this code is irrelevant to the question
                //Picking items from parent array. selectedExercises is a subarray
                for num in randomInts {
                    //allExercises just contains every possible item to pick from
                    self.selectedExercises.append(self.allExercises[num-1])
                }
                //now we have our selected workouts
                //Both print statements successfully print out correct information
                print("SELECTED EXERCISES: ", self.selectedExercises)
                cell.randomSelectedExercises = self.selectedExercises
                print("PRINTING FROM CELL: ", cell.randomSelectedExercises)

                
                
                
                //clear the arrays so we have fresh ones through each iteration
                self.selectedExercises.removeAll(keepingCapacity: false)
                self.allExercises.removeAll(keepingCapacity: false)
            } else {
                print("COULD NOT FIND WORKOUT")
            }
            
        }
        //***This works as expected - workoutName is visible in cell***
        cell.workoutName.text = name
        
        
        //clear the used arrays
        self.allExercises.removeAll(keepingCapacity: false)
        self.selectedExercises.removeAll(keepingCapacity: false)
        
        return cell
    }

Below is the code that gives me a problem in the cell swift file. the randomSelectedExercise does not have any data in it when I enter this area. This is an issue because in my for loop I am iterating from 1 to randomSelectedExercise.count. If this value is 0, I receive an error. The issue is focused in the UIStackView initializer:

import UIKit
import Parse

//Constants
let constantHeight = 50

//dynamic height number
var heightConstantConstraint: CGFloat = 10


class RoutineTableViewCell: UITableViewCell {
    
    //will hold the randomly selected exercises that need to be displayed
    //***This is where I thought the data would be saved, but it is not... Why???***
    var randomSelectedExercises = [PFObject]()
     
    static var reuseIdentifier: String {
        return String(describing: self)
    }
    
    // MARK: Overrides
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        commonInit()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
        
    }
  
    private func commonInit() {
        contentView.addSubview(containerView)
        containerView.addSubview(workoutName)
        containerView.addSubview(stackView)

        NSLayoutConstraint.activate(staticConstraints(heightConstantConstraint: heightConstantConstraint))
        
        //reset value
        heightConstantConstraint = 10
    }
    
    //MARK: Elements
    

    //Initializing workoutName UILabel...
    let workoutName: UILabel = {...}()

    
    //***I RECEIVE AN EMPTY ARRAY IN THE PRINT STATEMENT HERE SO NUM WILL BE 0 AND I WILL RECEIVE AN ERROR IN THE FOR LOOP***
    lazy var stackView: UIStackView = {
        let stackView = UIStackView()
        stackView.backgroundColor = .gray
        stackView.translatesAutoresizingMaskIntoConstraints = false
        

        //not capturing the data here
        print("rSE array:", randomSelectedExercises)
        var num = randomSelectedExercises.count
        for i in 1...num {
            let newView = UIView(frame: CGRect(x: 0, y: (i*50)-50, width: 100, height: constantHeight))
            heightConstantConstraint += CGFloat(constantHeight)
            newView.backgroundColor = .purple
            let newLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
            newLabel.text = "Hello World"
            newView.addSubview(newLabel)
            stackView.addSubview(newView)
        }
        
        return stackView
    }()
    
    //initializing containerView UIView ...
    let containerView: UIView = {...}()

    //Setting the constraints for each component...
    private func staticConstraints(heightConstantConstraint: CGFloat) -> [NSLayoutConstraint] {...}
        

}

Why is my data not properly transferring? How do I make my data transfer properly?

Edit

I believe I understand the problem better now thanks to @DonMag, so thank you very much. My data is not transferring properly because I am initializing my custom cell (creating the UILabel, UIStackView, randomSelectedExercise) with the default values I have given it. Then I am trying to update randomSelectedExercise afterwards, which will do me no good with my current code for stackView.

In respect to this, I have made a couple of changes and have omitted my background query as I felt it overcomplicated things for me. In my parse database, I have added the attribute associatedExercises to my Workout class. This attribute will contain an array of PFObjects of all the exercises associated with the working. At the beginning of this process, I have access to the selectedWorkouts which I iterate through when creating each cell in my table view, which is simply called workout in my cellForRowAt function. Following this, I extract the associated workouts data and put it into allExercises array. This is all I have changed since the initial question.

For full transparency, I will be pasting the entire code from the two files in question, followed with the questions I have now:

DisplayRoutineViewController.swift

import UIKit
import Parse

class DisplayRoutineViewController: UIViewController, UITableViewDelegate, UITableViewDataSource{

    var workoutDict = [PFObject:Int]() //Int is how many of the object was picked from the previous VC
    var selectedWorkouts = [PFObject]()
    
    var allExercises = [PFObject]()
    var selectedExercises = [PFObject]()
    
    @IBOutlet weak var tableView: UITableView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        tableView.delegate = self

        // Do any additional setup after loading the view.
        print(workoutDict)
    }
        
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "RoutineTableViewCell") as! RoutineTableViewCell
        //cell...
        let workout = selectedWorkouts[indexPath.row]
        
        //get the information we need - just the name at this point
        let name = workout["name"] as! String
        var randomInts = [Int]()
        
        allExercises = workout["associatedExercises"] as! [PFObject] //new attribute in Prase database
        
        let loopNumber = self.workoutDict[workout]!
        print("This is for: ", name)
        let maxExercises = self.allExercises.count
        //needs to be a while loop so i have control over iterator
        var iterator = 1
        var breakFlag = false
        while iterator <= loopNumber {
            var n = Int.random(in: 1...maxExercises) //will give us numbers inclusive 1 through maxExercises
            print("Random Number = \(n)")
            
            if randomInts.isEmpty {
                //case for when randomInts is empty
                randomInts.append(n)
            } else {
                //case for when randomInt does have n in it
                for i in randomInts {
                    breakFlag = false
                    if n == i {
                        iterator = iterator - 1
                        breakFlag = true
                        break
                    }
                }
                //case for when randomInts does not have n in it
                if breakFlag == false {
                    randomInts.append(n)
                }
            }
            print("This is randomInts array: ", randomInts)
            iterator = iterator + 1
            
        }
        //at this point, we have randomInts filled with the numbers we need
        for num in randomInts {
            self.selectedExercises.append(self.allExercises[num-1]) //num-1 because indexes start at 0 and num is never 0
        }
        print("SELECTED EXERCISE HAPPENS NOW", self.selectedExercises)

        //tableView.reloadData() //maybe this will help? - no it does not just makes an infinite loop
        cell.randomSelectedExercises = self.selectedExercises
        cell.workoutName.text = name
        print("PRINTING FROM CELL: ", cell.randomSelectedExercises)
        //upload the cells stackview with the information

        //clear the arrays so we have fresh ones through each iteration
        self.selectedExercises.removeAll(keepingCapacity: false)
        self.allExercises.removeAll(keepingCapacity: false)
        
        return cell
    }
    
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return workoutDict.count
    }
    

}

RoutineTableViewCell.swift

import UIKit
import Parse

//Constants
let constantHeight = 50

//dynamic height number
var heightConstantConstraint: CGFloat = 10


class RoutineTableViewCell: UITableViewCell {
    
    //will hold the randomly selected exercises that need to be displayed
    var randomSelectedExercises = [PFObject]()
     
    static var reuseIdentifier: String {
        return String(describing: self)
    }
    
    // MARK: Overrides
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        commonInit()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
        
    }
  
    private func commonInit() {
        contentView.addSubview(containerView)
        containerView.addSubview(workoutName)
        containerView.addSubview(stackView)

        NSLayoutConstraint.activate(staticConstraints(heightConstantConstraint: heightConstantConstraint))
        
        //reset value
        heightConstantConstraint = 10
    }
    
    //MARK: Elements    
    let workoutName: UILabel = {
        let label = UILabel()
        label.font = UIFont.boldSystemFont(ofSize: 16)
        label.lineBreakMode = .byTruncatingTail
        // Setting the max number of allowed lines in title to 1
        label.numberOfLines = 1
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    //added a lazy
    lazy var stackView: UIStackView = {
        let stackView = UIStackView()
        stackView.backgroundColor = .gray
        stackView.translatesAutoresizingMaskIntoConstraints = false
        
        //make the views inside the stackview
        //not capturing the data
        print("Showing Captured Data", randomSelectedExercises)
        var num = randomSelectedExercises.count
        print("Expecting Number: ", num)
        for i in 1...num {
            //create UIViews
        }
        
        return stackView
    }()
    
    private let containerView: UIView = {
        // wrapper to contain all the subviews for the UITableViewCell
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private func staticConstraints(heightConstantConstraint: CGFloat) -> [NSLayoutConstraint] {...}

}

In my console, the print statements in lazy var stackView appear before any of the print statements in cellForRowAt because I initialize cell before these print statement. This is the issue DonMag I think was trying to point out to me but I do not understand how to switch the order of these outcomes. If I can do so, I'm guessing that information will pass to the cell correctly? Also, I have thought of doing
cell.randomSelectedExercises = self.selectedExercises before let cell = tableView.dequeueReusableCell(withIdentifier: "RoutineTableViewCell") as! RoutineTableViewCell but obviously the namespace cell has not been created yet.

Please let me know how to solve this. I am at a complete roadblock...