+1 for Slint! I worked with it for a while and enjoyed it quite a lot. Florian was working on a more glossy compinent library, not sure what has been made of it.

The DSL was pleasant but still had some rough edges. I think they made some nice QoL improvements in the latest releases, but I've not kept up with it. The compile times were quite something, though you can use the previewer tool to prototype faster.

Definitely worth giving Slint a shot, they learnt a lot from QML imo