I came to the conclusion that if I need to do that -- webapp-regenerated, parametric variable stuff -- I would either hook up headless FreeCAD in containers (which is now potentially a bit easier, because the work Ondsel did is open source), or set up replicad, e.g. https://replicad.xyz/docs/examples/gridfinity

OpenSCAD is simply not worth the pain unless you're using it to demonstrate abstract geometry.

Build123D or CadQuery could well be viable, though IMO both have slightly frustrating dependencies. But since they can both load STEP files then customisations can be applied to designs built mostly elsewhere.