I had the same problem.
For some reason, the Debian package wasn't installing /etc/hp/hplip.conf.
Adding that file with the following contents fixed the error, so the HPLIP utilities could find the models.dat file.
-------- [hplip] version=3.21.2
[dirs] home=/usr/share/hplip --------
I had the same problem.
For some reason, the Debian package wasn't installing /etc/hp/hplip.conf.
Adding that file with the following contents fixed the error, so the HPLIP utilities could find the models.dat file.
--------
[hplip]
version=3.21.2
[dirs] share/hplip
home=/usr/
--------