So I can't seem to find much information over traditional gamepad support for the Hololens 2 and Unity projects. I've heard that xbox controllers do work but I currently only have a Gamesir T4 Pro and I can't seem to get any input read in my Unity project with the classic and new input systems.
I can connect to the gamepad and it shows up in the Hololens, but it does not seem to provide any input. Does the Hololens not support generic bluetooth controllers?
So I was able to get this working, I've created a sample Unity project set up with gamepad support for future reference.
https://github.com/CocoaMilka/Hololens-2-Unity-Gamepad-Support
There were some manifest settings that needed to be enabled. And the controller had to be set to Switch mode.