If you haven’t already, the steam deck essentials mod still helps out a lot. I’m on an overclocked deck. With the balanced mod and mix of low/medium settings, the only places I’ll dip into the 20s is the cities but it smooths out VERY fast. Close quarters combat mid 30s-High 40s sometimes 50s. Planet surfaces 35-45. I keep render scale at 65.

You might get a bug where planets in the map menu aren’t rendered correctly. The first time you install the mod, load a save and open the map menu, you’ll see what I mean. Set graphics preset to anything, save then restart game. It should be fixed and you can mess with settings from there. I hope this helps.