Comment by avhon1

Just because you type dimensions in doesn't mean it's parametric. If you're manually patching meshes, you're almost certainly not doing parametric CAD! (This does match with my memories of SketchUp, beck when it was owned by Google. I had to fix holes and overlapping geometry by editing the .STL files in Blender before any of the primitive slicer programs could process them.)

OnShape and Fusion360 are fully parametric CAD programs. Another free-tier closed-source one is Siemens Solid Edge (the "Hobbyist" edition). FLOSS parametric CAD programs that are reasonably usable are FreeCAD (complicated but powerful) and SolveSpace (an 80/20 sort of tool -- nowhere near as powerful, but vastly easier to use).