In order to control some devices on my machine, I have to apply the following two udev rules:

SUBSYSTEMS=="usb|hidraw", ATTRS{idVendor}=="1e71", ATTRS{idProduct}=="2006", TAG+="uaccess", TAG+="NZXT_Smart_Device_V2"
SUBSYSTEMS=="usb|hidraw", ATTRS{idVendor}=="1e71", ATTRS{idProduct}=="170e", TAG+="uaccess", TAG+="NZXT_Kraken_X2"

The first one does not alter proton behavior in any way, while the second makes my Xbox series controller (connected via usb) completely invisible to all games run via proton. Native Linux applications outside of proton are not affected.

I took the following screenshots from dolphin emulator run via proton, as it clearly shows all detected input devices. The controller effectively disappears after enabling the second udev rule.

Proton versions prior to 9.0-4 are not affected, while either PROTON_DISABLE_HIDRAW=1 or SDL_GAMECONTROLLER_IGNORE_DEVICES=0x1e71/0x170e can be used as workaround on later versions.

Here is a log generated with PROTON_LOG=+hid of a game refusing to see my controller:
steam-837470.log