https://wccftech.com/xenoblade-chronicles-definitive-edition-modded-handheld-mode/

Xenoblade Chronicles Definitive Edition can be made to run much better and with slightly improved visuals in handheld mode with some tweaking of the game's config files.

Reddit user breadedcaviar reported a few hours ago that disabling TMAA and letting the game use the 460mhz GPU profile makes dynamic resolution more stable, removes stuttering when panning the camera and slightly improves visuals.