find arguments generated by for loop through array?

I write a bash script to search through directories using the find command with different -iname arguments.
I want to pass -iname arguments to the find command by using a for loop. The strings for the -iname arguments are stored in an array.
I want to loop through the arguments to generate -iname ${arr[$i]} -or expressions.
Finally I add a single -iname ${arr[${#v_end[@]}-1]} argument without -or

The final find command should be like

find -L $destDir (-iname "*.mp4" -or -iname "*.AVI -or -iname "*.MTS")

My script:

#!/bin/bash
destDir= '/share/Multimedia2/VideoLink/tmp'
v_end=("mp4" "AVI" "MTS");
arr_len=${#v_end[@]};
arr_len=(($arr_len--))

find -L $destDir \(( for ( i=0; i<$arr_len; i++); do ( -iname "${v_end[$i]} -or" ) done ) -iname "${v_end[$arr_len]}" \)  

This doesn't work. What do I have to do to pass the for loop results to the find command?

What you have on the find command line doesn’t look like Bash at all.

I wouldn’t recommend expanding the array in one go, mainly because the script should support spaces and a few other (somewhat) common (somewhat) special characters in file names, which is hard to do while expanding an array and interleaving it with other tokens.

One can e.g. prepare the command line as another array and expand that one:

#!/bin/bash
set -euo pipefail

# Prepare some files to search for:
tmpdir="$(mktemp -d)"
trap 'rm -Rf "$tmpdir"' EXIT
cd "$tmpdir"
touch a b c A B C

# Prepare arguments for find:
inames=(a b c)
find_args=(-false)
for iname in "${inames[@]}"; do
  find_args+=(-or -iname "$iname")
done

# Show and call the find command:
echo find "${find_args[@]}"
find "${find_args[@]}"

One possibility might be:

#!/bin/bash

destDir='/share/Multimedia2/VideoLink/tmp'
v_end=("mp4" "AVI" "MTS")

for ext in "${v_end[@]}"; do
    args+=('-o' '-iname' "*.$ext")
done

find -L "$destDir" \( "${args[@]:1}" \)