"no" is reductive to the point of being misleading.

Cosmic DE is built using iced which is a rust gui library. As far as native, single-platform guis go, I'd say rust is plenty mature.

There's also Bevy, a rust game engine, which, if I'm not mistaken is built on egui(?), and I think supports multiple compile targets.

Between a desktop environment and a game engine, I'd say rust is in a pretty decent place when it comes to gui.

> There's also Bevy, a rust game engine, which, if I'm not mistaken is built on egui(?)

Not entirely correct, they have bevy_ui as the in-house example but many people use the third party bevy_egui crate