I don't know whether Hollow Knight uses an input library (like SDL) that would allow controller tweaks, but it might be worth investigating.

Steam generally gets games with poor/rigid controller support to work via Steam Input, which creates a virtual device that behaves like an Xbox controller and maps the real controller's inputs to it. You're not using Steam, but this project does the same sort of thing, and might be helpful:

https://github.com/chrippa/ds4drv

I don't know if it's still maintained, but if it chokes on a new distro, one if its forks might work.

I don't know what sort of background service you're using to convert game controller inputs to keyboard inputs, but I'm definitely curious, like what software/service are you attempting to use for that?

With that said, try this.. Try starting the game with the controller disconnected, and then only after starting the game, then connect the controller.

I don't know about your particular configuration, but in my experience, if there's no controller connected when you start the game, then the game won't see game control inputs after connecting a controller. But the background service most likely will see the controller and act strictly as a virtual keyboard device.

Please oh please keep me updated and let me know if this advice works, I'm very curious but don't have your game or exact setup to test it on..

Okay. This sounds very strange, but I had a similar issue with the nintendo switch pro controller and binding of isaac. I played around with antimicrox, but the real solution I found was to launch steam and leave it running. Then, my pro controller would magically work.

I didn't have to launch the game via steam either, which is what made it even stranger to me.