BDStudio is an online tool that lets you use the new block, item, text display entities to create a complex custom model that works in Vanilla MC!
It has a very nice dark interface that Blockbench users might enjoy, and an (unorganized, but) sizeable community.
https://eszesbalint.github.io/bdstudio/editor
There’s also a sharing site for BDStudio models in the works by another person. I haven’t seen anyone talk about it but it looks interesting. ^ ^
It looks amazing!