> The idea of doing DOM manipulation in a language that is not Javascript
...is already possible, see for instance:
https://rustwasm.github.io/docs/wasm-bindgen/examples/dom.ht...
You don't need to write Javascript to access the DOM. Such bindings still call JS under the hood of course to access the DOM API, but that's an implementation detail which isn't really important for the library user.
Dart also has this and as you can see in the examples in the README the APIs look exactly the same as what you are used to in JavaScript but now are fully typed and your code compiles to WASM.
While technically possible - the calls to javascript slow things down and you're never going to get the performance of just writing javascript in the first place, much less the performance of skipping javascript altogether.