This is a large part of the problem. In general, you never want to use pip to install complex packages (packages involving compiled binary libraries). The pusimp error explains the problem.
Edit: /usr/lib/petsc/lib/python3/dist-packages/dolfinx/__init__.py is correct (I missed petsc in the middle in my first reading).
You can find FEniCS installation instructions at https://fenicsproject.org/download/