Thanks a lot! We unfortunately are aware of the lack of functionality on Itch.io to properly populate metadata. We handle this by adding some additional mandatory fields to fill in when submitting the entries.
If you are interested please check our project Homebrew Hub - we’re building an open digital repository providing accurate metadata and emulating capabilities for homebrew software - and we’re currently working on the new draft of the Game metadata schema ;) If you’re interested in contributing feel free to hit me up on the gbdev discord (or @avivace).