Borrar todos los archivos excepto algunos de una carpeta usando applescript

Tuve un problema similar y lo solucioné de esta manera:

(*
Apple Scritp to Delete Files in all Startup and auto-launch Folders
    with dialog box to choose Delete or Cancel
    Uwe @UweTheSailor May 2022

    Exception handling for Roguea files (the Piezo App)
    added by Uwe in July 2022
*)

-- Variable Declaration Launch Deamons
set xyz to alias "Macintosh HD:Library:LaunchDaemons:"
-- Counter i increment to repeat loop (for loop)
set i to 1
set listOfNames to {}
set ItemNr to 0
set RmFile to 0

-- Loop all folders and check if there are files in the Startup and Launch Folders:
repeat until i = 4
    -- empty the list before filling it up again!
    set listOfNames to {}
    -- Fill the List "listOfNames" with files in the folder:
    tell application "Finder"
        set filelist to every file of the xyz
        repeat with currentFile in filelist
            set currentFileName to (the name of currentFile)
            -- exception for the two files, do not copy into list and do not remove from folder
            if currentFileName != "com.rogueamoeba.aceagent.plist" and currentFileName != "com.rogueamoeba.acetool.plist" then
                copy currentFileName to the end of listOfNames
                set AppleScript's text item delimiters to {" " & return}
                set ItemNr to ItemNr + 1
            end if
        end repeat
    end tell
    -- Only show dialog when Folder is empty (=content of listOfNames is Zero)!
    if length of listOfNames = 0 then
        display dialog "    There are " & length of listOfNames & " files in the folder: 
    " & xyz with title "Folder is empty!" default button "OK" giving up after 5

        -- Only offer Delete if there are files in the folder! 
    else if length of listOfNames > 0 then
        -- Display a dialog window with buttons and auto Cancel if no interaction after 10 seconds:
        set theButton to button returned of (display dialog "The Folder contains " & length of listOfNames & " files as follows: 
" & listOfNames with title "Found Files in the " & xyz with icon caution buttons {"Cancel", "Delete"} default button "Cancel" giving up after 5)
        -- Move all Files to the Bin if Button Delete is pressed
        if theButton is "Delete" then
            tell application "Finder"
                repeat until ItemNr = 0
                    delete (item ItemNr of (xyz))
                    set ItemNr to ItemNr - 1
                end repeat
            end tell
        end if
    end if

    -- Increment i + 1 and move to the next folder
    set i to i + 1
    -- Update the variable xyz to the next folder
    if i = 2 then
        set xyz to alias "Macintosh HD:Library:StartupItems:"
    else if i = 3 then
        set xyz to alias "Macintosh HD:Library:LaunchAgents:"
    end if
end repeat

Espero que esto te ayude a entender cómo manejar las excepciones. Estoy seguro de que hay formas más sofisticadas de hacerlo, pero para mí esto es suficiente. Saludos.