Especially if we want to use QtWidgets, the API surface is huge. There are a bunch of bindings with different language, but even the ones that are officially supported like PySide will still be second class citizen and awkward to use.
Automated binding generation will never give you idiomatic API in whatever language. And if you want an idiomatic library that wraps Qt, it's going to take a huge amount of work.
Which is why I think restricting to QML makes sense because that's a much smaller API surface. That was the ambition behind my previous crate that exposes QML to rust: https://github.com/woboq/qmetaobject-rs/
But now I've moved on to another GUI project: Slint https://github.com/slint-ui/slint It is implemented in Rust, but from the start aim to expose its API to several programming languages so bindings can be made idiomatic in almost every programming languages.