Both the back paddles and gyro are things that are great, and every gamepad should have them, but there's almost no compatibility with anything on PC.
Most I've ever seen is being able to change a button to a back paddle. Not even remapping a key, just a face or shoulder button. I swap it with the stick press buttons (L&R3). But it'd be great to be able to actually remap keys.
Steam itself has remapping functionality to extend any gamepad with customization. You can remap (and much more than just rempap) all keys and elements of a gamepad through the Steam Controller setup. People have uploaded their configurations, so you can download them. But this extended custom functionality is only for Steam.
I was talking about the custom profiles with Steam Input layout created by the community. Not sure if any game has this by default made by the game developers. https://partner.steamgames.com/doc/features/steam_controller/browse_configs (the link talks about the Steam Controller, but the concept is the same on Steam Deck)
You can technically stream your game to your deck, and it will work as a controller. If you have the OLED deck you can use something like magicblack Decky plugin to turn off the screen while playing