You might want to check out Dune3D. It advertises itself as combining the constraint solver from SolveSpace with a OpenCASCADE geometry kernel supporting fillets and chamfers. :)

Haven't used it much apart from some minor tests (I tend to prefer MoI3D, but that's in a different category in several ways...), but as far as FOSS solid modelers it seems like the most promising to me. I do remember some small UI quirks, but overall it felt very approachable and streamlined, and looking at the GitHub repo, development is active. FreeCAD IMHO is just too sprawling and complex, with seemingly little tought paid to UI/UX.

Agreed: The Dune3D developers made the wise decision to start from scratch implementing a parametric modeling UI. Extremely robust software; very fast, and almost intuitive (high praise for CAD).

The problem with FreeCAD, on the other hand, is that it's a "just two more weeks and it'll be great" solution.

The developers are clearly talented in a raw-math kind of way, but FreeCAD offers the eternal promise of usability in the next release; while never delivering it.

Those who are profoundly cynical might consider the possibility that the legacy CAD industry has infiltrated the FreeCAD development team and run Pied-Piper ops there to prevent a Blender-moment stealing their revenue.

This would perfectly explain why the FreeCAD experience is so consistently bizarre.