I'd say, it depends.
I don't know much about Ionic or Flutter, just that Ionic got voted to be a rather bad framework in the Stackoverflow developer survey. Also, RN was created because frameworks like Ionic have bad performance.
When things like React-Native-DOM get traction, RN will also add a reliable way to make Web apps with one code-base.
On the other hand I only heard good about Flutter, the only thing that keeps me from it is Dart, hehe.
Ionic wasn't mentioned at all in the last SO survey. If you're referring to Cordova, it was on both the most dreaded and most loved, so maybe there's a correlation.
Ah okay, I had the impression Ionic was always used with Cordova.
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