I do not believe this is due to me running an instance of Core 17.2 in VM (testing purposes).
Before beginning and due to it being fresh, I run the upgrades first.
I saw that fwupd-signed was held.
Cause - missing dependency of fwupd-unsigned.
Ran
sudo apt install fwupd-unsigned
This installed. Then ran the command to install fwupd-signed only to hit the same error. The package installed (latest version) was 1.1.4. The set dependency for fwupd-signed is fwupd-unsigned-1.1.1-4
Solution was to run to downgrade the package:
sudo apt install fwupd-unsigned=1:1.1-4pop0~1643174914~22.04~f30da97~dev
Then install the held package:
sudo apt install fwupd-signed
*Some users may need to run
sudo apt --fix-broken install
before trying the above.
This results in an ever-present message when apt update is run: 1 package upgradable. Either fwupd-signed or fwupd-unsigned but a user cannot upgrade both without removing one.