When you run freecad, the GUI starts, but it displays the following error:

During initialization the error "libTKMesh.so.7: cannot open shared object file: No such file or directory" occurred in /home/mmp/.local/share/FreeCAD/Mod/kicadStepUpMod/./InitGui.py

Practically nothing works, because of this error. The reason for the error is because the current opencascade package is not compatible with the current freecad package. The upstream Arch package has a patch included, which fixes this issue. I tried to build freecad-0.21.2 with the upstream patch and it worked for me:

https://gitlab.archlinux.org/archlinux/packaging/packages/freecad/-/blob/main/PKGBUILD

I also have to remind that there was another file called branding.xml that was added into the Parabola's PKGBUILD file, but it's not included into the Git repository. I've attached a patch with all the changes needed to build freecad-0.21.2