I changed how i look at communities when i switched to lemmy. Instead of just looking at the part before the @ i look at the whole thing and consider that to be its name.

So instead of the gaming community its gaming@xyz.qr and gaming@abc.de as a whole.

Tl;dr: theyre different separate comminities and the name is for all intents and purposes the entire thing.

I suggest subscribing to all of them for the topics you want and slowly through exposure learning which ones youd like to keep.