As I recall, retro deck installs an emulation hub that you go into, and then choose what to emulate.
Emudeck installs a bunch of individual emulators and configures them, and also sets up roms so they show up as standalone games in your library. The end result is the games feel like steam games, and you rarely have to mess with anything showing them to be emulated titles.
I think being cancelled can affect small groups and fan bases, but doesn't have any impact on the larger population.
It didn't help that boycotting it didn't make much sense. The game itself goes out of it's way to make sure it's "inclusive", actually boycotting it will hurt a lot of people involved in the game more than it would hurt Rowling. Supposedly the royalties are very minor for stuff that doesn't actually include any of the Harry Potter storyline, and JK Rowling is already richer than God.