I have never seen cross-platform UI that would work and/or look close enough to native. It has always been classic "choose any two": cross-platform, UI, great.
There were many people who claimed they have achieved all three, but at the close examination all of them, 100% without exception, were missing many little things like standard shortcuts, respecting color preference in user settings, or just couldn't see the difference between 11pt and 13pt fonts while looking directly at them.
10 years ago I worked on rewriting Qt interface of a desktop app back to native for a similar reason, and now I am reading all the same story except it's about React Native in mobile apps.
There were many people who claimed they have achieved all three, but at the close examination all of them, 100% without exception, were missing many little things like standard shortcuts, respecting color preference in user settings, or just couldn't see the difference between 11pt and 13pt fonts while looking directly at them.
10 years ago I worked on rewriting Qt interface of a desktop app back to native for a similar reason, and now I am reading all the same story except it's about React Native in mobile apps.