Is there a method in AppleScriptObjC (not System events) to send a copy (or cut or paste) event to the active application?
No. Generally speaking, there’s very little you can do to other apps.
That’s what I suspected.
Thanks, Shane.
Without knowing your use case, I don’t know if this will help, but FWIW, Keyboard Maestro has very effective Cut, Copy, & Paste actions. Of particular note:
The Cut and Copy actions wait until the clipboard changes before proceeding.
You can call KM Macros and Actions from AppleScript, as well as call AppleScript from KM.