Like I said I don't know about the itch app, but I might be able to help a little bit.
Renpy saves on Mac are supposed to be stored in $HOME/Library/RenPy/ and then a Yuri University folder. If the app uses the same file type, which I assume it does, at the very least I could either help you reconstruct your lost save, or even just give you a little boost to speed through the early game easier.
I won't finish making the game for at least a year, so that would be a big wait, but totally understand 😥