True, you don't need 4k 120fps ray tracing or whatnot to make a good game, but on steam deck in order to play 3A titles at acceptable framerate, you usually have to reduce settings to medium-low and run the game at 720p. I saw in a god of war benchmark video, in order to improve fps above 30fps, you also need to turn down rendering resolution to like 60%..
I like the idea of a powerful handheld gaming console that can play pc 3a titles, but right now the technology just isn't there yet. Maybe I'll pick one up in a few years (if they still make them after the hype died down), but definitely not now.