These controllers were all working on SteamOS before as far as I know, so I’m interested to see what this changes. My understanding is that previously their controllers just show up as generic xbox controllers, and now they will be properly recognized. We’ll see if this has any other benefits like custom bindings for back buttons and things like that.
Edit:
According to @dualpad@lemmy.zip
got the 8bitdo Ultimate 2 wireless controller with the latest firmware update, and can confirm dinput mode lets me map the back buttons and extra bumpers to different inputs through Steam Input. Analog triggers and gyro work too.
I have a Pro 2 too and switched from Xinput to Dinput at the back of the controller and my Steam Deck now identifies the back buttons like L4/R4 (but with the name PL/PR) and I can map it to anything I want