After updating, mopidy was disabled.
I had to manually run
sudo systemctl enable mopidy
to enable mopidy again.
This resolved the issue.
Posting here for posterity.
Effective config:
https://paste.ubuntu.com/p/ssgHc3qzFc/
Installed dependencies:
https://paste.ubuntu.com/p/wvDrrZGfQQ/
Hardware:
Raspberry Pi Zero W
Pirate Audio 3W