metroid prime 1 and 2 ran flawlessly on the steam deck apart from some lag spikes (to be expected with shader compiles or new rooms loading in), but prime 3 just has some rooms or cutscenes where it's just barely too much and it drops to 50fps, which also results in the game itself running slower and music and sounds becoming... "wobbly"
decided to install decky loader and powertools and doing the recommended settings change and now it's a silky smooth 60fps even in massive rooms that had trouble before!