Arguably, Flutter has had even more work done... it's incredible how Flutter tools work so beautifully on all OS's.
I've played with Compose for Desktop and it's basically the Android framework, but running on desktop, as you might expect... but the tooling is currently not anywhere as good as Flutter IMO... and the customizations to make apps look like actual desktop apps (rather than mobile apps on Desktop which is just horrible) is currently impossible because there's just no docs on how to do it or any library that helps achieve that that I could find... Flutter, on the other hand, has multiple "themes" that work well on Desktop... I was amazed to watch a YT video where a Flutter guy showed how he implemented a Windows 3.1- like theme for Flutter and re-created a really old app for a customer that, for users, looks just like the old one (which was a strong requirement by the customer!).
I've played with Compose for Desktop and it's basically the Android framework, but running on desktop, as you might expect... but the tooling is currently not anywhere as good as Flutter IMO... and the customizations to make apps look like actual desktop apps (rather than mobile apps on Desktop which is just horrible) is currently impossible because there's just no docs on how to do it or any library that helps achieve that that I could find... Flutter, on the other hand, has multiple "themes" that work well on Desktop... I was amazed to watch a YT video where a Flutter guy showed how he implemented a Windows 3.1- like theme for Flutter and re-created a really old app for a customer that, for users, looks just like the old one (which was a strong requirement by the customer!).