Pretty sure it isn’t.
Back in classic a guild got perma-banned for messing with game files to get a world first boss kill. And blizz put in place a way to make sure the files are left as intended.
I don’t know if any addon can do that either but there might be one.
You can change anything that is in your client ( client is on your computer )
I doubt there is anyway to detect that u change things like a screen .
Hacking occurs when u are trying to change things on the server .
My 2 cents : It’s prolly gonna take u a while till u figure out how to modify your client .
There was a a ban wave last year exactly because of modding the client. So yes, I’m pretty sure they can detect modified files. Be prepared to lose your account if you do it.