Is it common for the toolkits written from scratch in Rust to have bindings for other languages?

I still think the ideal solution for Desktop GUIs would be the Qt company developing first class Qt bindings for Node.js (or some other runtime), and allow people to build UIs using web tech with Qt components.

Slint UI does have bindings in other languages, but tutorials and docs are still lacking. Qt Bridges is a new option on the way for leveraging Qt with Rust and other language bindings.

Link: https://www.qt.io/development/qt-framework/qt-bridges

Qt already has really good binding, see Pyside6 for instance. GTK similarly through introspection.

Not sure why you want to build desktop GUIs using web tech though.