Supreme Commander has been a very fun RTS - that barely worked on Windows.
FAF, or Forged Alliance Forever brought it back to life with my friends, where it rebuilt lobbies, shored up a lot of the patchy netcode, and made it fun - but as we know modding and linux gaming can be tedious.
Until I found this repo, where FAF now fully “supports” Linux! It was such a breeze, it found my Steam install, my copy of Forged Alliance, and it set everything else up. Huge kudos to the maintainer!
Fellow RTS guy here, SupComm works prettt well in linux for me