I recently updated my system to Ubunutu 20.04, and my python is now 3.8. Since then all my import vtk lines don\'t work,
I was having your same problem: I have built VTK from Kitware but then I got error importing vtk in python. I fixed adding vtk in $PYTHONPATH, you should find it under VTK/build/lib . Everything works fine for me now!
EDIT: I found also that on the Kitware site the wheels for python3.8 are available, then:
pip3 install https://www.vtk.org/files/release/9.0/vtk-9.0.0-cp38-cp38-linux_x86_64.whl
should work as well