Even though it's challenging to navigate to the correct license location, Fusion 360 is still free for hobbyists and is more like OnShape than anything else out there. It can be fully parametric as well. I'm a fan of OpenSCAD, but recognize that it's not for everybody. BlockSCAD is pretty limited if one is creating sophisticated models, in my opinion. I've tried in BlockSCAD some simple models previously coded in OpenSCAD and found the software can't do it. Research effectively shows "we don't implement that capability." No big deal but BlockSCAD is indeed limiting in many ways.