Based on the description elsewhere in the comments, they don’t sound very similar. ProtonPlus is just a download tool that lets you see and download or delete updates for all the various versions of Proton, so you don’t have to visit a bunch of different Githubs. It doesn’t let you see or change which version each game is using, which it sounds like ProtonUp does.
I’m not sure how ProtonUp works with native games, installed outside of Steam or Heroic for instance, but it certainly doesn’t allow for per-game Proton version changes with Steam games.
EDIT: I was wrong, there’s a separate list I wasn’t aware of where you can change per-game versions. You can do the same thing in ProtonPlus FWIW.
This is akin to ProtonUp, with more compat forks available to download within the GUI.
Based on the description elsewhere in the comments, they don’t sound very similar. ProtonPlus is just a download tool that lets you see and download or delete updates for all the various versions of Proton, so you don’t have to visit a bunch of different Githubs. It doesn’t let you see or change which version each game is using, which it sounds like ProtonUp does.
I’m not sure how ProtonUp works with native games, installed outside of Steam or Heroic for instance, but it certainly doesn’t allow for per-game Proton version changes with Steam games.
EDIT: I was wrong, there’s a separate list I wasn’t aware of where you can change per-game versions. You can do the same thing in ProtonPlus FWIW.