I love QCAD, but I am very curious if there are any 2D modeling/drawing programs with constraints. Let me know if you've used on and would recommend it.
Do you mean 2D-only CAD programs? Because you don't have to go 3D with SolveSpace, nor do you have to go 3D with CAD Sketcher for Blender (it uses a Python port of the SolveSpace's solver).
Yes, FreeCAD can export 2D. See https://wiki.freecadweb.org/Manual:Generating_2D_drawings