I just tried the app, but unfortunately, it only lets me download/install the public version.
I've also now submitted a ticket to Itch.io support.
I think it's an error on Itch.io's part.
Because I noticed that I bought the game for 6.00€ back then for the Fluffy Edition v0.35.
If I bought the game again, only this time for 6.99€, would the Fluffy Edition be unlocked again? (As you can see in the screenshot, since it's not grayed out)
It's annoying that this price change is now locking me out of the Fluffy Edition.
I don't think you intended for people to have to rebuy the game after certain updates, right?