Thank you for your reply!
I have actually tried moving the web downloaded game to the app's default download location or to a download location I added and then letting the app scan to recognise it, but that didn't work. That's why I'm asking for help.
Of course, this does not affect my ability to play the game normally. It's just that games downloaded by the itch.io app seem to update automatically, so I'd like to try the app recognising games I've downloaded from the web and updating them automatically as well.
If not, I'll consider downloading the update manually or re-downloading the game in the app.
Anyway, thanks for reading and answering my question! Best of luck with your health! Have a great life! All the best!