Lost in DateTime in powershell

I somehow is lost in DateTime in Powershell

My Function To validate DateTime. Note It was sleeker but I was lost so started explicit returns of Good Bad. Don't Mind that. I want to capture the following

1. Start Time and End Time entered is correct (not junk)
2. End Time is bigger than Start Time
3. End Time is larger than current Time in UTC
4. Start Time is larger than current time in UTC

function IsValidTimeStamp($startDate,$endDate)
{
    [ref]$parsedDate = (Get-Date).ToUniversalTime()
    if (!([DateTime]::TryParseExact($startDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))){
            return ("Bad")
        }
    elseif(!([DateTime]::TryParseExact($endDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))){
            return ("Bad")
        }
    elseif(!(Get-date $([datetime]::ParseExact($endDate,"M/dd/yy H:mm",$Null))) -gt (Get-Date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null)))){
            return ("Bad")
        }
    elseif((Get-date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow)){
            return ("Bad")
        }
    elseif((Get-date $([datetime]::ParseExact($endDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow)){
            return ("Bad")
        }
    else
        {return ("Good")}
}

Now when I enter the a proper date which is less than current UTC time
$startDate = '03/20/23 14:00' & $endDate = '03/20/23 14:30'
Something is not correct. Most Likely the statement

elseif((Get-date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow)){
            return ("Bad")
        }
 elseif((Get-date $([datetime]::ParseExact($endDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow)){
            return ("Bad")
        }

Strangely if you see both the results are returning false as even though I am using a not operator

I am calling the function like this below

 if ((IsValidTimeStamp $($LINE.Start_Time) $($LINE.End_Time)) -eq "Good"){
                #Basic validation of DateTime is successful 
               ###Do something else ###
}
else{
       echo "Failed to validate dateTime"
}

As asked below copy pasting the commands ran on the console

PS D:\Maintenance-Window> $startDate = '03/20/23 14:00'

PS D:\Maintenance-Window> $endDate = '03/20/23 14:30'

PS D:\Maintenance-Window> [ref]$parsedDate = Get-Date

PS D:\Maintenance-Window> !([DateTime]::TryParseExact($startDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))
False

PS D:\Maintenance-Window> !([DateTime]::TryParseExact($endDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))
False

PS D:\Maintenance-Window> !(Get-date $([datetime]::ParseExact($endDate,"M/dd/yy H:mm",$Null))) -gt `
            (Get-Date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null)))
False

PS D:\Maintenance-Window> (Get-date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt `
            $([System.DateTime]::UtcNow)
False

PS D:\Maintenance-Window> !(Get-date $([datetime]::ParseExact($startDate,"M/dd/yy H:mm",$Null))).ToUniversalTime() -gt `
            $([System.DateTime]::UtcNow)
False

If you look closely the last two commands are exactly the same one with the Not symbol in front. Since the input time has passed than current UTC time I expected a True.

EDIT Final Script

function IsValidTimeStamp($startDate,$endDate)
{
    [ref]$parsedDate = (Get-Date).ToUniversalTime()
    if (!([DateTime]::TryParseExact($startDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))){
            return ("Bad")
        }
    elseif(!([DateTime]::TryParseExact($endDate,"M/d/yy H:mm",[System.Globalization.CultureInfo]::InvariantCulture,
        [System.Globalization.DateTimeStyles]::None,$parseddate))){
            return ("Bad")
        }
    elseif(!((Get-date $([datetime]::ParseExact($endDate,"M/d/yy H:mm",$Null))) -gt (Get-Date $([datetime]::ParseExact($startDate,"M/d/yy H:mm",$Null))))){
            return ("Bad")
        }
    elseif(!((Get-date $([datetime]::ParseExact($startDate,"M/d/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow))){
            return ("Bad")
        }
    elseif(!((Get-date $([datetime]::ParseExact($endDate,"M/d/yy H:mm",$Null))).ToUniversalTime() -gt $([System.DateTime]::UtcNow))){
            return ("Bad")
        }
    else
        {return ("Good")}
}

function IsValidTimeStamp($startDate, $endDate){ 
try { (get-date) -lt $startDate -and [datetime]$startDate -lt
$enddate } catch { $false } }

get-date
Monday, March 20, 2023 2:13:58 PM

isvalidtimestamp 3/21 3/22
True

isvalidtimestamp 3/21 3/20
False

isvalidtimestamp 3/21 3/21
False

isvalidtimestamp 3/23 3/24
True

isvalidtimestamp 3/23 0/24
False

When comparing two datetime ranges there are 7 different results