A machine should be able to interpret topographic lines and generate an architectural floor plan that minimizes cut and fill.

If you're getting your engineering plans from Midjourney etc., something is likely to explode.

To be honest from the sample prompts they provide you would be lucky if any two pieces fits together.

It's like the joke about the group of engineering professors who were invited to fly in a plane.

After they get comfortably seated, they are informed that the plane was built by their students.

All but one jump out of their seats and immediately run for the exits.

Later, the lone professor who remained calm was interviewed, as he clearly had more confidence in the ability of his students than any of the others.

“It's true, I know my students' ability very well, and I can tell you for a fact this plane won't move an inch.”

What is the Architectual equivalent of a hand with twelve fingers and nonsense lettering

a McMansion

Probably the Winchester Mystery House: https://en.wikipedia.org/wiki/Winchester_Mystery_House

That or gothic cathedrals: https://en.wikipedia.org/wiki/Gothic_architecture

Depends on what it is. I use DALLE3/midjourney to give me ideas for furniture pieces all the time and then build them. This is obviously not as complicated as a CAD for a building but it’s still a great starting point.

that's not really suitable for the manufacturing/building route

That kind of vectorization is a royal pain to edit.

inkscape is pretty go at everything except simplification.