If you are looking for Steam Deck compatibility, PrismLauncher has a page for bootstrapping it to look nice on Deck. PrismLauncher does also support controller navigation, though this breaks for me on my Steam Controller when using SteamInput rather Xinput. Perhaps this is different for the deck's controls?
Obviously for desktop, there isn't much point to doing this unless you really make use of big picture mode.
Authentik has blueprints, which while not as simple as Authelia's config, do provide a functional way to have version-controlled configuration.