The Docker documentation is pretty terrible, but it’s a decent start. Start by looking at docker-compose.yml files for the services you want to run and the write-ups for those.
Something nobody ever told me, that I had to figure out myself, is that docker-compose.yml files can be placed anywhere you want.
Bingo. I will happily go out of my way to modify things, and if the methods provided to hide root/bootloader ststu from any particular app don’t work, then that app gets uninstalled.