I’ve been playing MHWorld on my steam deck OLED (low settings) at a consistently smooth 60fps. The only hiccup is the new map introduced in the Iceborne DLC (hoarfrost reach, the area covered in snow) hovers around 55-57.

Side note, I’m afraid they’re going to bork MHWorld in an update too. Which would be hugely disappointing as I’ve easily put 100 hours into the game on deck alone.