I wish more people knew how good Flutter for desktop already is. So far it's a competitive advantage for early adopters.
I think in Flutter, you do not define the interface in HTML. That is a no-go for me. I think HTML is the UI language that will outlive all others in existence. It would be a mistake to use something else and then have to rewrite everything in some years.
HTML is a typesetting engine. It's not a "UI language" and never has been.
I don't know why would anyone think it's a good choice to do UI apps. The fact we use it on a web is a historical accident and causes a lot of pain and damage to the industry.