Probably have to use Windows to update it. Once the proper firmware is applied then going into dinput mode on the 8bitdo Ultimate 2 wireless controller allowed me to map the back buttons and extra bumper buttons through Steam Input. Was also able to set up gyro too.
I play this game with the Steam Controller using motion controls and without aim assist, and do fine against mouse and aim assist players.
So this is a game that when you die isn’t usually due to someone having much better reflexes and pixel perfect aiming than you. More game sense and good utilization of gadgets and specialization. Which to start off will be rough not knowing what everything does, but once you become familiar with it should become less of a problem.
I 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.