How to stop PowerShell function changing return type of ArrayList or string[]

I'm attempting to return either a .NET ArrayList collection or a string array
(string[]) from a PowerShell function. PowerShells runtime "unravelling" is not
behaving as described, and the various work arounds I've read about don't address
the issue.

What is being returned is also not what I expect or have read about.

The following code returns a System.Array with a count of 6 and the values
0 1 2 A B C. What I want is only 3 values A B C.

function GetArrayOfStrings([string[]] $strings)
{
      # set up a collection to "read them in"
      $stringAryList = New-Object "System.Collections.ArrayList"
      foreach($string in $strings)
      {
            $stringAryList.Add($string)
      }

            $stringAry = $stringAryList.ToArray()
            return $stringAry
}

#main

$stringAry = GetArrayOfStrings(("A", "B", "C"))

foreach($str in $stringAry)
{
      Write-Host $str
}

The returned  values suggest PowerShell is flattening a hash table where 0 1 2 are the index values and A B C the content values.

Attempting to "wrapper" the return using "," or @(,) syntax doesn't improve things much.

      return ,$stringAry
      return @(,$stringAry)
      
Both result in a System.Array containing {0, 1, 2, System.Array} and an output of

0
1
2
A B C

This is better, but the only way to get the string[] as a System.Array is to do the
following:

$actualStringArray = $stringAry[$stringAry.Count-1]

Some of my readings online have suggested the array is unravelled to make it simpler
for human readability or to be used in foreach, but I certainly don't see how...

I have identical problems when attempting to return the ArrayList

Looking for a way to fully defeat the unravelling or a way to use the results in a foreach,
but only for the content values, not the index values.