I’ve never used the itch.io windows app. Would there be any downsides to just uninstalling and reinstalling it (after making a backup of the settings)?
Hm. Personally, I use Windows 7, but maybe the issue stems from the method you used to reinstall Windows 10.
If any other software has acted up since then, you might find help on a board dedicated to Windows. Because if there is one thing for certain in this world, it is that people will talking with each other about their problems with Windows. ;)