Thanks for the link, I will watch it when the opportunity comes.

However it is like the sibling comments mention, this hasn't been properly managed as message to the UI/UX community.

So when someone used to Forms, WPF/Blend, Qt Designer, Interface Builder, Delphi, C++ Builder, Swift UI, Flutter, JetPack Composer,... sees blogs and tutorials where .ui files are written by hand and direct use of GtkBuilder is praised, eventually all interest is gone.

Anyway, thanks for the link and for jumping in