Yeah, "AAA games on high / beautiful graphics settings" isn't really the Deck's forte. FSR upscaling covers up a lot of the worst of docked ugliness, but it has its limits.
If visual fidelity is a huge deal for someone, and they are going to play docked 90%+ of the time, then they'd probably have been better served by a gaming laptop instead of a Steam Deck. And if one picked up the Deck because it was the best overall value for what they could afford, then they should probably be happy with the capabilities it has, and adjust their expectations a bit.