You can download the core here [Core] Dolphin for MuOS V9 Take 3 by @Speedrun [+.[🐬].%] - #3 by arkun
the compatibility list is here https://docs.google.com/spreadsheets/u/0/d/1LHXQV78yAuvii8J77KUgEt3Ap6TagjQzN48gdB9iVKY/htmlview I’ve got Pikmin to work but I haven’t tested anything else.
Edit 1: also if you add a GameCube icon also add one for the Wii because the links to the core I provided are for both Wii and GameCube. I got rhythm heaven fever to work