I definitely had my eyes on slint for quite some time (pretty much since it was announced - I highly value the technical skill of their team) but it's still quite far from the whole QWidget offering. I don't know anything else that is even remotely in the same ballpark - certainly not Tauri or egui for instance. Anything that is GPU based is blacklisted from the get go (including QtQuick) - people who preach gpu based GUI have definitely never tried to have a quick debug feedback loop with an app built using AddressSanitizer where just opening the simplest GL or Vulkan context takes up to 20 seconds on a good day.

Slint is not a replacement for Qt. Slint only provides a tiny fraction of what Qt has to offer https://doc.qt.io/qt-6/modules-cpp.html

Name one of those plenty suitable options rust have to replace something like Qt.