Hello,
A key way in which our network stack integrates with docker has been officially removed in the latest release. We have been aware of this eventuality for awhile, and have been working towards a replacement. More news to come on that later.
In the meantime, please upgrade to the latest supported version that came out a couple weeks ago, with:
apt update
apt install docker-ce=5:20.10.23~3-0~debian-bullseye docker-ce-cli=5:20.10.23~3-0~debian-bullseye
Note: If you have already upgraded to the latest version and your docker installation is not working, the above command will resolve the issues.
Once that is done, go ahead and pin docker to that version:
apt-mark hold docker-ce docker-ce-cli