I think Flutter is an interesting candidate for 'cutting edge' cross-platform mobile and desktop GUIs not based on HTML/CSS. Qt Quick/QML might be another, stil

I think Flutter is an interesting candidate for 'cutting edge' cross-platform mobile and desktop GUIs not based on HTML/CSS. Qt Quick/QML might be another, still relevant technology, at least on the cross-platform desktop. See also e.g. https://drops.dagstuhl.de/storage/01oasics/oasics-vol109-evcs2023/OASIcs.EVCS.2023.25/OASIcs.EVCS.2023.25.pdf https://drops.dagstuhl.de/storage/01oasics/oasics-vol109-evc...