Just found out there is a way to launch sonic mania via retroarch
!!!!maybe you also need to setup a working wii system nand/menu in retroarch can´t say for sure!!!!
so long you know how dolphins works in retroarch and how to make advanced changes to dolphins settings in retroarchs user folder
here are the basics
1. get the Sonic Mania Wii port (decomp)
2. make an sd image via dolphin standalone and edit the RA dolphin config
3. runs via the homebrew channel .wad file with dolphin
forum link for further discussion
https://forums.libretro.com/t/running...