Hi,
first of - where did you get the idea/read that TurnKey Core comes with Docker pre-installed? (Not to mention that docker-compose is normally a separate component to install).
So if you really plan on using Docker, do so by creating a (Debian 11) VM - Docker provides a nice
installation guide for such situations.
Running Docker in an CT is just asking for trouble - it
might work, but things will break subtly in some way or another.