Easy, it is likely docker that is making your Mac mini slower than your old linux box?

Docker on macOS is painfully slow, because it is implemented on macOS through what amounts to a sledgehammer to the problem. Docker depends on linux kernel features so on macOS it just starts a linux virtual machine and does other high overhead compatibility tricks to get it to work. Volumes are the biggest culprit.

If you are running docker through rosetta... (don't know the state of docker on apple silicon) then that is a double whammy of compatibility layers.

Regarding bugs, yeah probably teething issues because the M1 was/is such a large departure from the norm. They should really get those things fixed pronto.