I don't know about GTK, QT, and the like, but there's a whole budding ecosystem purporting to solve it WASM-native.
Dioxus [1] and about a dozen other libraries are attempting to be write-once, deploy web, mobile, desktop with native performance. They adopt a React-like component UI.
The Rust ecosystem is full of stuff. There are lots of different approaches too - immediate mode drawing, canvas drawing [2], etc.
Choosing a winner is the hard part. There are too many projects and no clear community-elected leader.
GTK+ has Broadway to render GTK applications to the web browser. Qt has some ActiveX support, but you don't want that. Java/Kotlin has a bunch of frameworks, like TeaVM to run .JAR files in the browser, or Vaadin to write web GUIs like you would desktop applications.
I think most languages that have been around for more than five years have some kind of GUI framework that'll run in the browser.
Very worst-case scenario, you could compile a Windows executable and run them in BottledWine :P
Dioxus [1] and about a dozen other libraries are attempting to be write-once, deploy web, mobile, desktop with native performance. They adopt a React-like component UI.
The Rust ecosystem is full of stuff. There are lots of different approaches too - immediate mode drawing, canvas drawing [2], etc.
Choosing a winner is the hard part. There are too many projects and no clear community-elected leader.
[1] https://dioxuslabs.com/learn/0.4/getting_started/wasm
[2] https://www.egui.rs/#demo