It seems like a lot of games that would be green/verified are classed as yellow/playable solely because of small text, which is equivalent to being verified if you use your docked Steam Deck as a cheap gaming PC first and a handheld second.

Yeah but the situation isn't limited to deck, though deck makes it worse since the screen is smaller than average monitor.

Modern games without a big ass high res monitor will have text that's too small to be enjoyable.