Fix HP printer software after upgrade (on Arch Linux)

I am trying to run HP's printer software which was upgraded recently and broke all my printing. I run a constantly upgraded Arch (which is 5.10.14 as of Feb 28, 2021). Apparently they use Qt now so it is some kind of requirement so I spent 2 hours building all this Qt stuff. It seems crazy that HP is requiring linux users to spend hours building obscure packages just so they can print. lpstat -a says the printers are ready and working/idle, but nothing can print to them. The cups log says the print failed to a "backend error". Anyway, hp-setup now just hangs on startup and hp-check gives an error that PyQt4 cannot import QtCore, which is the standard way PyQt users try to verify the version of Qt they are running under. So, apparently there is some kind of version conflict between the two. Here is the relevant section of my pip list:

PyOpenGL              3.1.5
pyOpenSSL             20.0.1
pyparsing             2.4.7
PyQt3D                5.15.2
PyQt4-sip             4.19.24
PyQt5                 5.15.2
PyQt5-sip             12.8.1
PyQtChart             5.15.2
PyQtDataVisualization 5.15.2
PyQtPurchasing        5.15.2
PyQtWebEngine         5.15.2

So, is the problem that I have PyQt5 on my system and the HP software wants PyQt4? If so, can I have both on the same system? What is the procedure to diagnose this?

$ sudo find /usr -name "PyQt*"
/usr/share/qt/qsci/api/python/PyQtDataVisualization.api
/usr/share/qt/qsci/api/python/PyQtPurchasing.api
/usr/share/qt/qsci/api/python/PyQtWebEngine.api
/usr/share/qt/qsci/api/python/PyQt3D.api
/usr/share/qt/qsci/api/python/PyQt5.api
/usr/share/qt/qsci/api/python/PyQtChart.api
/usr/lib/qt/plugins/PyQt5
/usr/lib/python3.9/site-packages/PyQtChart-5.15.3.dist-info
/usr/lib/python3.9/site-packages/PyQt5_sip-12.8.1-py3.9.egg-info
/usr/lib/python3.9/site-packages/PyQtPurchasing-5.15.3.dist-info
/usr/lib/python3.9/site-packages/PyQt4
/usr/lib/python3.9/site-packages/PyQt5
/usr/lib/python3.9/site-packages/PyQt3D-5.15.3.dist-info
/usr/lib/python3.9/site-packages/PyQtDataVisualization-5.15.3.dist-info
/usr/lib/python3.9/site-packages/PyQt4_sip-4.19.24.dist-info
/usr/lib/python3.9/site-packages/PyQt5-5.15.3.dist-info
/usr/lib/python3.9/site-packages/PyQtWebEngine-5.15.3.dist-info
/usr/lib/python2.7/site-packages/PyQt4
/usr/lib/python2.7/site-packages/PyQt4_sip-4.19.24.dist-info

The output from HPLIP_DEBUG=1 hp-setup:

HP Linux Imaging and Printing System (ver. 3.21.2)
Printer/Fax Setup Utility ver. 9.0

Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

hp-setup: debug: param=
hp-setup: debug: selected_device_name=None
hp-setup: debug: Using PyQt5
hp-setup: debug: Sys.argv=['/usr/bin/hp-setup'] printer_name=None param= jd_port=1 device_uri=None remove=False
hp-setup: debug: Starting GUI Event Loop...
Searching... (bus=net, timeout=5, ttl=4, search=(None) desc=0, method=slp)
error: No devices found on bus: net
error:  HPLIP cannot detect printers in your network.  This may be due to existing firewall settings blocking the required ports.
                When you are in a trusted network environment, you may open the ports for network services like mdns and slp in the firewall. For detailed steps follow the link.
                 http://hplipopensource.com/node/374