Popos also has specific guides for these common errors:

https://support.system76.com/articles/bootloader

mumble works very well and is foss as well.

Ok, if it tries to mask as another game, maybe it’s best to start the game with a (fake) steam account. (Enable compatibility mode for proton for the game on steam).

You have found the right tool in lutris. You basically just use the plus button to either install your game or point to one that’s already on your drive. Watch a tutorial somewhere if questions remain. Also install proton-up to install the newest version of proton-ge easily. Most games will run with the newest proton-ge version.

If a game does not start, check first the right exe is used by lutris and the wine path needs to point to each games root folder. Sometimes Microsoft .net framework has to be installed for a game.