Not a single user cares about "native ui", it's only a debate among developers. Take the top 20 apps people are using, all of them use their own design system which isn't native.

Flutter will always have multiple advantages against React Native (and even Native toolkits themselves) in terms of upgradability, you can do 6 months of updates with only 30mins of work and make sure it 100% works everywhere.

The quality of the testing toolkit is also something which is still unmatched elsewhere and makes a big difference on the app reliability.