
I've only changed the system to 40 fps to get a little extra battery juice out of the Steam Deck.
After initial full screen success, the game now launches into a smaller window frame. It can be successfully fixed after changing the window to either borderless or windowed, confirming, and then swapping back to full screen.
It's an easy fix, but one I'll tinker with to try and avoid in the future (and update if anything works).

Locked to 50fps/50hz in the overlay so I could retain max settings. Keeps power draw between 10-14w.
There was one area top left of the map that would tank performance for no reason at all (utilisation just drops). It's very brief and I was only able to repeat it once. Only time it happened in over thirty hours of gameplay.
Works out of the box, you can also play at 60 if you drop render scale to 2. But 50fps was fine for me.

Either lock at 30FPS or change the Render Scale to 2 at 60FPS to reduce battery usage.
I've played on both my Arch desktop and on the steam deck. Works out of the box with no issues!

Perfect
Lowered the TDP to 10w without any impact on the performances

I just put it on experimental and it worked out the gate. One of the favorite games of all time, I hope you too can enjoy the journey!

Works out of box flawlessly.

Works out of the box
The game installed, launched, and showed correct controller glyphs out of the box. No tinkering needed.