For once we get a good support request with a detailed description of the symptoms, attempted troubleshooting steps, and relevant context. Show some respect and read the thing before insulting OP’s intelligence

Have you tried reading the post? They already did

I never heard of AltGr reffered to as “Meta”, except maybe in the sense of “Emacs modifier” which might be bound to it. Super is definitely the key between LCTL and LALT though

You can use Meta or Super as a more agnostic term

Not what you asked for, but you may be interested in getting a keyboard running QMK where you can define these kind of modifier overloading (and much much more) on the keyboard itself, so it’s “portable” and doesn’t require OS/DE settings