that nobody told me that i had to use the app instead the web for me to actually to be able to use the option of the c: user data app etc
Are you trying to tell us, that you have a renpy game that has a different save game location depending on wether you use the itch app to install it, or installing it manually?
Because that would be quite curious. Renpy games have two save locations, and one of them is the installation folder and the other is the user folder mentioned above. And that user folder is not dependant on the install location.
Did you maybe use the sandbox mode of the itch app? That creates a new user to run the games for safety reasons. That new users has it's own Appdata folder.