ARMORED CORE VI FIRES OF RUBICON is the big new release developed by FromSoftware Inc, the same team from ELDEN RING and it does seem to run quite well on Steam Deck and desktop Linux.
Plays somewhat well, but I get an amdgpu gfx_timeout crash within seconds of starting the Baltheus fight. This is apparently a known issue with the game itself (something about shaders not being calculated properly, which given the boss has a ton of particle effects, makes sense) so I'll have to wait til that gets fixed. https://github.com/ValveSoftware/Proton/issues/7045#issuecomment-1693816570