I remember it being bad enough for a project I was working on that the engineer working on it switched to relm: https://relm4.org

It is built on top of gtk4-rs, and fairly usable: https://github.com/hackclub/burrow/blob/main/burrow-gtk/src/...

I'm sure the gtk-rs bindings are pretty good, but I do wonder if anyone ran Valgrind on them. When it comes to C interop, Rust feels weirdly less safe just because of the complexity.