Always use . The RetroArch core for ScummVM is older, lacks many features, and can suffer from input lag. In ArkOS, make sure ScummVM is not hidden: Options → Advanced → Enable Experimental Touch Support (this also affects how standalone apps are treated).
To make ScummVM run "better" on ArkOS, you need to move beyond the basic folder-dragging and utilize specific automation scripts and persistence fixes that address common ArkOS-specific bugs. 1. Automating Game Recognition arkos scummvm better