Honestly surprised this wasn't already a rule. The number of times I've bought something on day one and the first thing I see is a launcher error or a missing DLL is kind of absurd for a store that takes 30%.
The Steam Deck Verified stuff makes it worse, because people trust that badge. If a patch breaks the game on Deck and the badge stays up for weeks, that's on Valve too, not just the dev. Five minutes of a human launching the actual depot would catch most of the dumb ones: wrong launch option, wrong exe, Linux script pointing at nothing.

