Ok. Looks like a much more straightforward way to install the latest duplicity is via snap. I know some people have strong opinions about snap, but I do not, so I installed that way and it worked without issue.
root@mailbox:~# apt remove duplicity
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages were automatically installed and are no longer required:
librsync2 python3-fasteners python3-monotonic python3-nacl python3-paramiko
Use 'apt autoremove' to remove them.
The following packages will be REMOVED:
duplicity
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 2231 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 115471 files and directories currently installed.)
Removing duplicity (2.2.0-ppa202401271616~ubuntu22.04.1) ...
Processing triggers for man-db (2.10.2-1) ...
root@mailbox:~# rm -rf /etc/apt/sources.list.d/duplicity-team-ubuntu-duplicity-release-git-jammy.list
root@mailbox:~# snap install duplicity --classic
duplicity 2.2.0 from Kenneth Loafman installed
root@mailbox:~# rm -rf /usr/bin/duplicity
root@mailbox:~# which duplicity
/snap/bin/duplicity
root@mailbox:~# duplicity --version
duplicity 2.2.0 January 17, 2024
One big benefit here is that it migrates you to the stable release channel, as opposed to the git PPA, which is a nightly release and has the potential for unexpected bugs, as we’ve seen in the last few days.