GNOME was focusing on building Rust bindings for GTK for many years before Qt development picked up. The GTK bindings were usable within a year or two after Rust’s 1.0 release. Yet even today, those looking to build applications in Rust will find that GTK is the only mature toolkit right now. And if you’re doing that today, I’d recommend starting with Relm4 for the best GTK Rust experience.
Rust does not support the C++ ABI, and Qt does not provide a C interface, so much work has to be done on building the tooling for binding C++ libraries to Rust. That work is still ongoing, so some have opted to use QML instead of interfacing with Qt C++ libraries. Yet if you’re looking to use Qt or QML, you may as well use Slint instead. It’s developed by former Qt/Trolltech developers and has a similar approach as QML.