Gluon is dead as RoboVM is.
RoboVM never worked properly for FX and without it things will be worse as OpenJDK is an interpreter on iOS. Even discarding that FX has inherent unfixable problems on iOS, Adobe couldn't get Flash to work properly on iOS and those guys don't understand graphics/GPU nearly as well as Adobe did.
We do have a new Windows port, it's already open source although isn't in production yet:
https://www.codenameone.com/blog/new-windows-port.htmlXamarin never supported Windows. That's visual studio. Their approach to mobile development is inherently flawed as it relies on a custom low level VM where they have to keep chasing the native platform rather than use its existing tools.