I would also recommend checking out SALOME for 3D modeling. I’ve been using the shaper toolbox to create geometry for fluid simulations and it’s worked well for me. The shaper toolbox is parametric (as opposed to SALOME’s geometry toolbox which is not).

After you’ve created your geometry in shaper you switch to the mesh toolbox to create your stl file. I think there’s really good control over the triangle creations with SALOME. For example, you can specify edges and faces you want smaller triangles in (like around tight geometries, holes, etc). I’ve been able to get much higher quality stl files with this method than with freecad.