HedgeModManager VS modmanager

Use STL to launch HedgeModManager by running ~/stl/prefix/steamtinkerlaunch hmm start

HedgeModManager: https://github.com/thesupersonic16/HedgeModManager/releases/

Quick update: No fix has worked for me unfortunately. I can get HMM booted and mods loaded but HMM will always crash when trying to boot Sonic Frontiers at the step 'Loading Codes'. I've documented my steps in the existing Github issue here: https://github.com/thesupersonic16/HedgeModManager/issues/219

At this point, trying to launch the game from Steam it would close. This is because the d3d11.dll file used by HMM is problematic and fails to complete when running in Proton. You'll need to manually delete it and replace it with this .dll file. (You'll have to rename it to d3d11.dll) You can read more about this current issue here if you're curious. Note: This means HMM will load MODS but not CODES. Here's hoping that compatibility will be fixed in the future.

Sonic GMI has been replaced by HedgeModManager which supports several sonic games and has code support which is pretty useful (I can't remember if sonic GMI does). Sonic GMI is much easier to make work on Linux while HedgeModManager is significantly more difficult. Here you can find instructions for hedgemodmanager on Linux. DO NOT FOLLOW THE TOP GUIDE, it apparently doesn't work as well and its for Sonic Forces. In the comments there is instructions and a script to run for Sonic Generations, make sure yo do everything it says. If you experienced issues which I have I can try to help you but as long as you follow the instructions I think it should be fine.

If you want a mod launcher to launch with all these mods, I'd recommend GDLauncher or PolyMC. If you are using the vanilla launcher, Mod Manager is great.