Works fine

Frequent audio stuttering
Frequent stuttering and significantly lower FPS than on Windows

-force-vulkan
After forcing Vulkan it worked like a charm

gamemoderun %command%
Prior to the most recent update, Native seemed to work perfectly well, but now the native client has some variety of memory leak when loading a save or starting a new game that forces me to fully reset my desktop. The same save I tried to load in Native functioned normally and without incident under Proton.
Works flawlessly
Crashes exist in later game but happen more frequently as game continues, almost one per year

R4 switched to bulid in steam deck's zoom in
By default text is small (but readable). Go to settings menu and increase GUI's scale to fix it.
Works fine out of the box.
I use left trackpad as mouse, and right trackpad as scroll wheel for zoom. Also eight stick is the arrow keys to move the view around.
Test is small, even with the UI zoom at max in the settings.
The early game is playable (and fun!) after messing with proton versions. I'm not sure the later stages of the game will also be bug-free.
Crashes starting after meeting other AIs
I've only clocked in an hour of game time, but everything has worked great thus far.
Solid native build.
Didn't test multiplayer.

I've tested the Epic Store version through the Heroic Launcher. Seems to work flawlessly out of the box.