Rust

Slint is pretty much the spiritual successor to QtQuick. I think it's written by people that used to work for Qt, it has a similar design (GUI focused DSL with automatic reactivity), and they are even using the same business model - basically free except for embedded use (cars, petrol pumps, PoS etc.). But without the decades of baggage Qt has and with support for Rust from day one.

It can even use Qt as a backend somehow.

I had a go with Slint because it does look impressive but tbh the amount of setup you have to do is just a bit too much compared to something like gpui-component. Probably worth it for a bit project I guess.