Hello again players!
We want to tell you that even we still don't have the Steam deck verified yet, the game runs perfectly on the small (big) machine.
We love Steam deck and we (the dev team) have two of them that we are using constantly to test the game on it, therefore we recommend you to use the default config, in case you need to restore it is:
Resolution: 1280x800
Graphics quality: High
Postprocessing: enabled
Volumetric lighting: enabled
Volumetric shadows: disabled
With those settings we guarantee that you will have a smooth and nice experience with 60 fps in most of the scenes, if you have any questions please don't hesitate to write in the forums or in our social networks.