I've got an RX580; it works almost flawlessly, including for games emulated via Proton/etc.. The only significant problem I've had was when I (unwittingly) received a new Mesa installation (I'm on NixOS/unstable, so, rolling release) and everything I'd already played stopped working. Took me a while to figure out I had to delete shaders that'd been cached for the older version of Mesa. I imagine most non-rolling distros wouldn't have that problem.
That should not happen on rolling release distros either - sounds like it would be a NixOS packaging issue where the version (or git commit hash) of Mesa/LLVM is missing or the Nix package applied patches without changing the version in the cache key.
