I've used WYSIWYG UI dialog editors (mostly the one MSVS used to bundle with C# in... I wanna say 2012?) that maintain their entire state as somewhat-editible two-way code (so if I modified the code, at least within a constrained envelope, it would be reflected in the editor and remain WYSIWYG editable).
Does that count?
If so, I think the lesson is you need to keep the no-code side way, way less ambitious than is theoretically possible in order to keep everyone sane and you might actually have a useful tool that doesn't dig you into a big hole.