I've went through the pain and made a working Layout for the Steam Deck.
Took a lot of testing hours to get it to work just right...

You should be able to find it on your Deck under Community Layouts

Z3R0B4NG
SteamDeck basic Keybinds (Proton 7.0-3)


Left Stick: up/down/left/right
Left Stick button: center view
Right Stick: roll left/right
Right Stick button: zoom

pause: ESC key
select: change camera view

L1: brake
R1: boost
L2: zoom
R2: fire lasers

D-Pad: wing man commands

Y: target nearest
X: manual target
B: fire secondary
A: fire lasers

No Gyro
No Trackpads
No Backgrip buttons


oddly enough with older Proton versions the ship just spins and with Proton-GE the controls are completely fubar, so make sure to force Proton 7.0-3 in the options.
Don't ask me why different Proton versions would mess with the keybinds like that... no idea.



OTHER STUFF;

I've tested every Proton version, i get a black screen in all of them for the videos,
pcgaming wiki has an entry how to skip the 2 intro videos, i guess if they don't play anyway we can kick them out...

Instructions[1]
Go to <path-to-game>\Game\Streams\Video
Rename, move or delete these files:
slintro.bik
lecintro.bik


And i have yet to find out how to get those registry changes for Widescreen adapted to Steam OS.

I've set the resolution in the launcher (touchscreen menu) to 1024x768 and use FSR to fill the remaining pixels, but it is 4:3 of course.