How can I reset controller configuration for a specific game in Steam?

Background

I own a PS5 controller, my operating system is Ubuntu 22.04. I installed a new game in steam, and it was listed as having partial controller support. I did not see any controller configuration in the "Controls" menu, so I set my controller to mimic a keyboard and mouse. However, this was terrible, so I decided to poke around in the options again, and for whatever reason, there were gamepad options displayed, and with a PS5 controller option, no less.

The Problem

Because I had previously used Steam's Controller Configuration menu, I cannot remove the existing controller configuration to pass through my controller, only replace the existing configuration, or alter it. So Steam recognizes my controller as a PS5, but when I select the "Gamepad" option, or try to manually set a layout, it defaults to setting my controller up as an Xbox controller. While I can technically use this, it means that the wrong buttons will be displayed in game, which is non-ideal.

What I would like

I would like to either:

• Erase Steam's controller configuration specifically for this game, thus forcing it to pass through the default config (My controller is currently set up fine with Steam (It recognises it as a Dualsense, not a Dualshock 4), and with other games, and it would be more than a bit of a faff to redo that work). Manual is ok. I am more than experienced enough to remove or edit a configuration file manually, to remove this config. I'm just unable to locate where game-specific controller bindings are stored.

• Set up a binding using Steam's Controller Configuration menu that outputs PS5 controls to the game. This is "less clean", however it still solves the problem. I was unable to wrangle the controller menu to do this, as the controller mapping buttons in the selection menu are all Xbox buttons.