Slint is released in v1.0. It is a toolkit for multi-platform UI development.
Developed in Rust, it has APIs für C++ und JavaScript, according to the article:
https://www.heise.de/news/Schlankes-UI-Toolkit-fast-aus-Berlin-Slint-benoetigt-weniger-als-300-KByte-RAM-8516264.html
The Slint project homepage: https://slint-ui.com/
It’s a very promising tool for Rust. I played around with it (and even got a license 
). But on a similar level as fyne.io for Go, just for Rust. It is no coincidence that the product was initially called SixtyFPS.
The GUI is defined in advance and then runs like a movie, dynamic changes(!) of the UI are therefore complicated / impossible. However, this is irrelevant for the current focus of the application area: embedded devices, small screens of devices and that is also the main focus of Rust.
Like fyne.io, it is certainly useful for smaller tools, i.e. a UI on top of a program that could also run in a console. Or on the web as WebAssembly / JS combo.
At least nothing that would allow the citizen developer IMHO a migration path from more complex Xojo apps to Rust, just as little as fyne could at the moment. If you think of cross development in this context, there is basically only a browser approach via Electron or Tauri, or Java (Swing, JavaFx) or waiting for Mauri . People who want to play with Rust should IMHO start with https://www.egui.rs/ (which can run in a desktop app too) as it s definitely easier to get started for beginners and the technical constraints you will encounter are similar.
As I am using RUST for embedded Devices I can say: yes, dynamic changes are important and needed. There is no such solution but I doubt that there will not be one in a year or two. But like @Jeannot already said: it is not a bit of a migration path for Xojo users like GO has also no migration possibility for Xojo users.
As a migration path there is C++, Java, C# (C# only for the Windows UI World, for the Mac- and Linux World there is nothing really reliable and stable released and MAUI is still not in a stage that it is ready for production).
C++ with WXWidgets works fine, with QT also, Java with Java Swing or Java FX works fine all of them for Desktop, C++ with QT mobile works fine, C# has mobile options but they are let me say: complicated!, Java has JavaFX and GluoMobile and it has CodenameOne. That are simply the migration paths for reliable, sustainable and usable migration away from Xojo world. And yes: there is a bunch of other Solutions but people will learn fast: not a good Idea.
waou so many new framework, seems like a new era after electron apps !
exciting period !
but as usual few will remains, GO or Rust ?
Both. Rust while firmware oriented development for rtos is perfect with rust, go for webapps