I have also long desired something like this. I'd love a parametric vector (+ image) editor; it's an unfilled niche. (If any startup people are looking for ideas, here's your million dollar opportunity.)

There are the CAD programs, like SolveSpace/AutoCad/QCAD, but they aren't really designed for illustration: you would have to constantly export the blueprint to style it. I think the closest you can get now is UI design software with constraint features, but that software isn't really made for free-form work like Illustrator/Inkscape.

This discussion may be of interest to you, though it is not UI-based and none of the software has been open-sourced (yet): https://news.ycombinator.com/item?id=21774018

EDIT: Looks like Inkscape can do a few vaguely CAD-like things with "live path effects", but it's by no means a proper constraint solver. See the feature request here for a full constraint solver, which includes a summary of past progress and proposals: https://gitlab.com/inkscape/inbox/-/issues/1465