For building instructions in the context of MFEM, see

• METIS 4.0.3: https://mfem.org/building/#parallel-mpi-version-of-mfem
• METIS 5.1.0: https://mfem.org/building/#parallel-build-using-metis-5

On new Macs (with ARM CPUs), use the patched version metis-4.0.3-mac.tgz.