I solved my problem by downloading hplip-3.20.9 and not installing the GUI (which requires the Python 2 lib python-pyqt5) or the Fax functionality (which requires Python 2 lib python-reportlabs). I installed hplip-3.20.9 and then after that the plugin hplip-3.20.9-plugin. Now my scanner works.
I solved my problem by downloading hplip-3.20.9 and not installing the GUI (which requires the Python 2 lib python-pyqt5) or the Fax functionality (which requires Python 2 lib python-reportlabs). I installed hplip-3.20.9 and then after that the plugin hplip-3. 20.9-plugin. Now my scanner works.