Hello everyone!

First off: I greatly appreciate devuan and use it every day on several machines! Thank you to all the contributors!

Now back to topic:

After fixing this issue using your guide (as well as a "apt-key del BB23C00C61FC752C" beforehand...),
I realized that the new GPG key also expires within a year...

I strongly recommend using individual GPG keys per release that do not expire before the respective release's end-of-life!

That also happens to be debian's approach from what I can see:

Debian/Buster key expires: 2027-04-12
Debian/Bullseye key expires: 2029-01-15
(says my "apt-key list" command anway)

You could take those expiration dates as template for your own keys and add a couple months or a year on top to account for the delay between debian releases and their respective devuan counter-part.

With the currently provided new key we can expect the exact same problem to happen next year,
that's why I would be happy if you could consider this approach.

Thank you!