Qt/QML? I have been doing cross-platform development with Qt for a few years now [1]. It does have a learning curve, but I do like the split of C++ logic and Qml for the UI. I can recommend the qml book [2].
Thanks, I've used it. I left another comment about it [0]. Perhaps I should give it another look. Qt doesn't really satisfy my desire to use something fun and relatively simple, but you and the other commenter are pointing out the obvious -- it is clearly a viable choice.
[1] https://screen-play.app/
[2] https://www.qt.io/product/qt6/qml-book