I've been on the main branch of Tcl/Tk I can confirm that the GUI and language situation is extremely good.
The announcement buries the lede but the Zipfs_Apphook is a gamechanger, I can use to package any app into single executable cross platform AppImage like thing (works great on Windows!).
Any app, it could be Java, JS whatever, just bundle everything (JRE, shared libs, static assets, whatever) into a Zip image & from the user POV it's just a single executable.