Hello @TheAnonym3000, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/8671#issuecomment-3729037068.
Anyone actually found a solution for the side panel working incorrectly yet
I just now stumbled upon the same behavior on Linux Mint 22.3 with my Logitech Heavy Equipment Bundle. The wheel and pedals works fine and is recognized in the game. The side panel is recognized as XINPUT_GAMEPAD and only half the buttons work and are just mapped to gamepad buttons which breaks a lot of functionality in the game. I'm watching #8671 but it looks like no progress was made yet.
Compatibility Report
System Information
I confirm:
steam-2300320.log
Symptoms
The Mad Catz Saitek Side Panel Control Deck (Not the Wheel) is being detected as XINPUT_GAMEPAD and some buttons work, while other don't.
Reproduction
Use the Mad Catz Saitek Side Panel Control Deck with FS25 using Proton and try to bind the buttons 1 (should work, being registered as "A") and 21 (Nothing happens)