
Everything just works.

Played docked with Keyboard and Mouse
Text to Speech is not supported on Linux which removes a bit of the game's charm

--enable-speech-dispatcher
After setting up speech-dispatcher + espeak-ng, speech synthesis test buttons in the BIOS and new save creation work but the game fails to detect it and uses the fallback option anyway.

Enjoyable experience
Fullscreened onto the wrong display, fixed it by dragging onto correct monitor in windowed mode then reenabling fullscreen

Intermittently slows down to a crawl.
Slow at times and Steam overlay doesn't open. Otherwise fine.
Works perfectly OOTB except Steam overlay doesn't open
Steam overlay did not open with shift + tab
Assign left trackpad to "scroll wheel"
The virtual assistant doesn't have text to speech functionality on Linux; instead, it'll make goofy mumbles.
Enable non-integer scaling in the "bios" menu to have Hypnospace Outlaw fill the Steam Deck screen. Plays fine without any issues.
Linux version doesn't use text-to-speech for Hypii, rather Hypii communicates using robotic noises (which are a fallback when TTS is not available). The game provides captions for Hypii's speech, so TTS is not strictly necessary.