Are you aware of / have you considered Gluon ? All-Java, with native (mobile) implementations (including look & feel) of JavaFX, if I understand correctly.
iOS, Android, cross-platform desktop (apparently).
I don’t think the company’s website provides sufficient information, i.e., you’d really have to chat with its sales reps and developers to evaluate either or both products. I get the impression that Gluon Desktop may have been orphaned. Again, a question or two would be required.
See also: