Wasn't there a retro engine decompilation project that could theoretically be used as the basis for a homebrew port of Sonic Mania to Wii U though? That would be so cool and probably doable for someone with enough time and knowhow, and a legal copy of the game.

"Uhm actually it's on Wii U via the Sonic Mania decompilation port for the Wii U" -Nerd Emoji