Flutter is just for people who need to get something basic done without too much trouble, I think. It's been over a decade of mobile UI iteration and we still don't have something that does everything for all OSes in a declarative way, so I think we are just doomed to writing a native app for each platform if you want performance, correctness in terms of UI, and productivity.
And on the other side there is Ionic which is has no real performance issues (contrary to flutter), has the biggest ecosystem (the web) and is elegant, expressive, simple ->
The thousands of powerful web APIs, Angular and typescript
