Yesterday, July 1st, they announced the Alpha release of this next-generation mod manager and their new Product Manager got in touch to mention they “would be really keen to get feedback from Linux users”. So this is your chance to ensure Linux (and Steam Deck) finally become a first-class citizen for game modding.
Not literally, but this turns your device into a Steamdeck, which is what you implied you wanted. With the option to launch into Big Picture/Gaming Mode.