I believe too they don't even waste time verifying indie games that have too few sales. My game was written for the Steam Deck but I don't hope to ever get my title "verified". I inly sold maybe 200 copies, ha ha.
I did for the Linux port (using CLion and CMake files). But as I've said, I ended up dropping it before shipping since Proton on Steam Deck ran my Windows port so well.
In the end, perhaps sadly, the Steam Deck was for testing only. I rarely boot into the Desktop any longer.
CMake, BTW, was a great way for someone like me who does not know Visual Studio to get something working on Windows. (Xcode is familiar to me so I didn't bother trying to generate the Xcode project from CMake.)
SDL2 is the amazing framework I found for cross-platform development. Just the right level of abstraction for my code-it-in-C game projects.
Funny enough I am also working on a game project and use SDL2 for the cross-platform aspects (I don't need to learn some incredibly specific IDE, I get the control, but it abstracts away all the more boring stuff), but I specifically want to target the Steam Deck for my next PC game project.