I would recommend joining our discord if you're able for more assistance!
Viewing post in Final Fantasy XI Braver comments
Hey!
I'm having the same issue this user was but might be able to offer more. When using the itch.io app, if you click on "download" the dialogue box the app throws up isn't allowing users to download because we can't select a version of the game to install. A quick look at helps posts for this says that dev's would need to assign platforms to version for the itch.io app to function: https://itch.io/t/1852361/no-game-files-available-to-install
I'm a steamdeck user that needs the app so if you get the chance to fix it that would be awesome!