

Works well out of the box

Runs out of the box

Game runs well
Completed all endings without problems
Set GPU Clock to 1000Mhz
Most dungeons and battles will run at 60FPS with occassional minor dips into the 50s, but it can drop as low as 40s or 30s in some specific areas, like Planeptune and (unexpectedly) the live2D scenes and world map. Part of this may be a programming problem as even locking it to 30 or 40FPS will still get you minor drops, but overall, it is very playable and has better performance than console. Speaking of the live2D scenes, I had to set the GPU clock at 1000mhz since leaving it at default settings will cause the GPU to go crazy during these parts, which revs up the fans and consumes your battery much faster than the 3D gameplay.
Runs without issues out of the box. Hit play and enjoy the game!
It runs at around 140FPS at 2560x1440
Switched to experimental to be sure but with that it worked out of the box

Set display refresh rate to 40hz.
No issues. Performance chugs a bit on the world map. An inconsistent 60hz is possible, but 40hz seems like the way to go.

While using default Proton: disappearing props and flickering textures in the prologue dungeon.
The game initially had some issues rendering the first 3D area whilst using the default Proton or the latest GE-Proton. I had a similar issue with a single level in Sonic Frontiers, so it might just be something with this system specifically. In both cases the issues didn't occur on Steam Deck, just this desktop. Proton Next seems to run the game perfectly. The game runs at 60 FPS solid for me, but I also get a jittery feeling somewhere. It feels like some parts of the game might update at less than 60 FPS internally, but that's just a guess. Overall the game looks and plays very well.
Lower TDP to 8 watts and cap to 40fps
40Hz 40FPS 10 watts CPU 900 GPU

gamemoderun %command%
Game is jittery while exploring and seems to suffer from input lag.
If you lock the frames at 40/50 FPS, you can play games in portable mode at 720p/800p without problems. In 900p and 1080p resolutions, on the other hand, to play at maximum detail, I recommend blocking the frames at 30 FPS.
To lock the frame rate you have to use the SteamOS beta features, as the game does not allow it from the settings.