Pretty low compromise in terms of portability; surprisingly good on Mac, has ARM support. I think on FreeBSD/OpenBSD as well via ports.
It is a bRep GUI CAD system with 2D drafting, 3D CAD, a technical drawing workbench, FEM, mesh tools etc., and now a core CAD assembly tool. It has a "workbench" (think GUI plugins for specific task) approach, supports macro recording of Python macros, has many third-party workbenches, It is constraints-based and fully parametric: designs recompute and reflow when underlying measurements change.
It's also a 20 year labour of love by a bunch of CAD users.
If you are familiar with QGIS, it's really a lot like that but for CAD. It's less like GIMP than some people say, but it is a bit like GIMP (and like GIMP, is in a long battle with a core architectural problem; FreeCAD 1.0 includes a big victory over its worst core problem)