I have two gamepads, both of which worked before the latest update, a Xbox One Gamepad and an SN30 Pro+, the SN30 works if connected via a USB cable, I can’t test the Xbox gamepad, as i don’t have a cable
They both connect and show up in the Bluetooth manager but don’t seem to detected by any programs.
The only way I’ve been able to fix it is to downgrade with timeshift.
I had an issue with my bluetooth controllers recently as well, starting with 5.10. In my case, things were failing to connect at all, but while working on it I found a few things that might be helpful.
If you’re using a 5.9 kernel, moving up to 5.10 might fix it.
You could also try deleting the controllers from your devices list, and then re-add/search them. (This is what fixed my issue.)
In regards to troubleshooting, checking journalctl for relevant errors and/or warnings might help you narrow down a cause. I don’t recall how to off-hand, but you can test joystick/controller input in/with evdev to see if it notices inputs at that level. If so, the problem might be something further down the line, such as with SDL or SteamInput, or what have you.