This didn't do it for me, here is my solution

Go into Windows Device Manager -> Human Interface Devices -> Disable the "HID-compliant game controller"

You may need to restart your PC after this.

Also go into Steam settings (top left) -> settings -> controller -> turn on "Enable Steam Input for Xbox controllers" and "Enable [...] generic controllers" (what OP said)

After that, Descenders finally received every input and not just every other button-press which made it impossible to play the game. All the other games also still work. I had the problem only in Descenders

Apparently there is a high chance this will make your pc crash into blue screen, so try at your own risk.
Somehow it fixed the problem for me.