> Writing in a non-compiled language already puts you in a disadvantage

Both Kotlin and Swift are compiled.

> But this is just the standard I set to myself - the entire industry clearly has different priorities.

I think you just underestimate the performance of Java/Kotlin/Swift, languages that you admitted you don't have any experience with.

> tho with good debugging tools and LLMs I have found this to not be a problem anymore

Again: try modern languages with good debugging tools and LLMs :-). I think your bias is that this is all you know.

> because I've proven that it is fixable by caring about UI/UX

It requires care, which means more effort. All that for being at best similar to the native tools, but probably never exactly the same. And it cannot be better, because the native ones are the ones defining how it should be.

> I can't stretch how FUN, easy, and overall a great experience to develop with QML and C++ together, it's just HOW GUI should always been

But you said you don't have experience with the native Android/iOS way. I personally have used QML/C++, Flutter, Android (Java/Kotlin, the old XML way and the new Compose way) and SwiftUI. QML/C++ is by very far the worst.

I would advise that you try either Kotlin/Compose or Swift/SwiftUI to get an idea. You can still use C++ to share some code (say you write a complex library in C++, no need to rewrite it in Kotlin and Swift), but starting a new mobile UI with QML these days is just madness IMHO :-).