Only keep the latest .var and it's associated files

i have a lot of files in subfolders with names like

\dave\dave.look1.1.var
\dave\dave.look1.1.jpg
\dave\dave.look1.1.txt
\dave\dave.look1.2.var
\dave\dave.look1.2.jpg
\dave\dave.look1.3.var
\dave\dave.look1.3.jpg
\dave\dave.look2.1.var
\dave\dave.look3.1.var

\bert\bert.look1.1.var
\bert\bert.look1.2.var
\bert\bert.look1.2.png
\bert\bert.look1.4.var

\fred\fred.look1.1.var
\fred\fred.look1.1.jpg
\fred\fred.look1.2.var
\fred\fred.look1.3.var
\fred\fred.look3.4.var
\fred\fred.look3.4.jpg
\fred\fred.look3.5.var
\fred\fred.look3.5.jpg

The end result should be something like this

\dave\dave.look1.3.var
\dave\dave.look1.3.jpg
\dave\dave.look2.1.var
\dave\dave.look3.1.var

\bert\bert.look1.4.var

\fred\fred.look1.3.var
\fred\fred.look3.5.var
\fred\fred.look3.5.jpg

where the digit is the version number but I only want to keep the latest .var (and it's associated .txt, .jpg or .png (may be others) with the highest number and delete the others in powershell.

So far I have the following which fails on the remove-item because the passed name no longer contains the version number?

# Set the path to the main directory containing the subdirectories
$mainDirectoryPath = "E:\Install\test\_New"

# Get a list of all subdirectories in the main directory
$subDirectories = Get-ChildItem -Path $mainDirectoryPath -Directory -Recurse
Write-Host "Found $($files.Count) files in $subDirectories"

# Loop through each subdirectory
foreach ($subDirectory in $subDirectories) {
    # Get a list of all files in the subdirectory
    $files = Get-ChildItem -Path $subDirectory.FullName -File

    # Group the files by the name before the version number
    $groupedFiles = $files | Group-Object { $_.Name.Split('.')[0,1] -join '.' }

    # For each group of files, keep only the file with the highest version number
    foreach ($group in $groupedFiles) {
        Write-Host "Processing $($group.Count) files for $($group.Name)"
        $group | Sort-Object { [int]$_.Name.Split('.')[2] } -Descending | Select-Object -Skip 1 | Remove-Item -Force -whatif
    }

@theo -
No that doesn't give me what i'm looking for:

Running against the following files -

AcidBubbles.Animations_Presets.1.jpg
AcidBubbles.BlendShapes.1.var
AcidBubbles.BlendShapes.2.var
AcidBubbles.ChloeTouch.1.jpg
AcidBubbles.ColliderEditor.36.var
AcidBubbles.ColliderEditor.37.var
AcidBubbles.ColliderEditor.38.var
AcidBubbles.ColliderTuner.13.jpg
Acidbubbles.Cornwall.2.jpg
AcidBubbles.Cornwall.2.var
AcidBubbles.Embody.53.var
AcidBubbles.Embody.57.var
AcidBubbles.Embody.58.var
AcidBubbles.FloatingUIComponents.3.jpg
AcidBubbles.Glance.11.var
AcidBubbles.Glance.16.var
AcidBubbles.Glance.19.var
AcidBubbles.Glance.20.var
AcidBubbles.RubberLeash.2.jpg
AcidBubbles.RubberLeash.4.var
AcidBubbles.Timeline.200.jpg
AcidBubbles.Timeline.210.var
AcidBubbles.Timeline.242.var
AcidBubbles.Timeline.248.var
AcidBubbles.Timeline.249.var
AcidBubbles.Timeline.250.var
AcidBubbles.Timeline.251.var
AcidBubbles.Timeline.252.var
AcidBubbles.Timeline.268.var
AcidBubbles.Timeline.269.var
AcidBubbles.Timeline.270.var
AcidBubbles.Timeline.271.var
AcidBubbles.Timeline.272.var
AcidBubbles.Timeline.273.var
AcidBubbles.Timeline.274.var
AcidBubbles.Timeline.275.var
AcidBubbles.Timeline.280.var
AcidBubbles.Utilities.5.var
AcidBubbles.Utilities.6.var

Gives -

What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Animations_Presets.1.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.BlendShapes.1.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.ChloeTouch.1.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.BlendShapes.2.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.RubberLeash.2.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Cornwall.2.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\Acidbubbles.Cornwall.2.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.FloatingUIComponents.3.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.RubberLeash.4.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Utilities.5.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Utilities.6.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Glance.11.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.ColliderTuner.13.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Glance.16.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Glance.19.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Glance.20.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.ColliderEditor.36.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.ColliderEditor.37.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.ColliderEditor.38.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Embody.53.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Embody.57.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Embody.58.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.200.jpg".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.210.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.242.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.248.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.249.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.250.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.251.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.252.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.268.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.269.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.270.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.271.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.272.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.273.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.274.var".
What if: Performing the operation "Remove File" on target "E:\_test\AcidBubbles\AcidBubbles.Timeline.275.var".

What I'm after is -

AcidBubbles.Animations_Presets.1.jpg
AcidBubbles.BlendShapes.2.var
AcidBubbles.ChloeTouch.1.jpg
AcidBubbles.ColliderEditor.38.var
AcidBubbles.ColliderTuner.13.jpg
Acidbubbles.Cornwall.2.jpg
AcidBubbles.Cornwall.2.var
AcidBubbles.Embody.58.var
AcidBubbles.FloatingUIComponents.3.jpg
AcidBubbles.Glance.20.var
AcidBubbles.RubberLeash.2.jpg
AcidBubbles.RubberLeash.4.var
AcidBubbles.Timeline.200.jpg
AcidBubbles.Timeline.280.var
AcidBubbles.Utilities.6.var

You should be able to do this with just one Get-ChildItem call:

$mainDirectoryPath = 'E:\Install\test\_New'
# first get all files with a basename that ends with a dot followed by a number
Get-ChildItem -Path $mainDirectoryPath -File -Recurse |
Where-Object { $_.BaseName -match '\.\d+$' } | 
Group-Object { $_.BaseName -replace '\.\d+$'} |   # first group on the BaseName without the version number
ForEach-Object {
    # next, within each of these groups, group again on the file extension
    $subgroups = $_.Group | Group-Object Extension
    foreach ($group in $subgroups) {
        # sort on the integer version value, highest number on top
        # select all except the first one and remove the rest
        $group.Group | Sort-Object {[int]($_.BaseName -split '\.')[-1]} -Descending | 
                       Select-Object -Skip 1 |
                       Remove-Item -Force
    }
}

Using your latest example files, after running this you will end up with these files:

AcidBubbles.Animations_Presets.1.jpg
AcidBubbles.BlendShapes.2.var
AcidBubbles.ChloeTouch.1.jpg
AcidBubbles.ColliderEditor.38.var
AcidBubbles.ColliderTuner.13.jpg
Acidbubbles.Cornwall.2.jpg
AcidBubbles.Cornwall.2.var
AcidBubbles.Embody.58.var
AcidBubbles.FloatingUIComponents.3.jpg
AcidBubbles.Glance.20.var
AcidBubbles.RubberLeash.2.jpg
AcidBubbles.RubberLeash.4.var
AcidBubbles.Timeline.200.jpg
AcidBubbles.Timeline.280.var
AcidBubbles.Utilities.6.var

^{P.S. In your desired output you forgot file AcidBubbles.RubberLeash.2.jpg}