I got my brother, who is not Linux-savvy, set up playing Clone Hero on his Steam Deck while I was thousands of miles away and it played with no input lag basically out of the box on SteamOS. If you’re looking for a good Guitar Hero experience on Linux with lots of custom songs, Clone Hero is for you.
If you’re looking for Guitar Hero with characters, venues, and no input lag on Linux I have nothing to suggest. :/