Really great battery life (3hrs) with Steamdeck set to 40 fps, TDP limit 8. In game set controller to "on" and XB360 (not automatic). In graphics options set: antialias quality low. Motion blur off. Ambient occlusion off. Screen-space reflections off. Still looks amazing. Much nicer than the Switch version (which I played for 100hrs) Use "subnautica-steamdeck" controller layout.