That's funny, I found it the exact opposite, not the least of which is that it requires a JetBrains IDE to even run it. VSCode or neovim with Flutter and really most every other UI framework like React (and Native) work great.

Regarding KMP specifically, I didn't find it much use to only write business logic in one language, while still having to rewrite the UI up to 6 times (mobile, web, desktop), I'd rather have everything all in one.

Compose Multiplatform looks promising as it's Flutter-like in that it renders its own UI but it's still quite early, I know they say it's "stable" but when I used it, it really didn't seem so, plus the package support is extremely lacking compared to Flutter and of course the behemoth that is React (and Native)'s npm.

These days I'm looking forward to Dioxus, they're making their own native renderer similar to Flutter but especially for web, they are not doing the canvas trick, because they actually use plain HTML and CSS as their markup languages so they can compile directly to browser standards sites while still having a non-webview experience on mobile and desktop.