As I mentioned in other comments, I’m a software dev that’s worked with companies that were doing this, that were talking to other mobile game companies that were doing this. I hate to say “trust me bro” but, this stuff isn’t something they’re like happy to publicly advertise so it’s not like it’s written up somewhere, AFAIK.
Yes, it requires it runs well with default settings, everything is accessible with the standard deck controls, that all the control displays use the steam deck icons, and it doesn’t reference controls the deck doesn’t have. It’s a very high bar.