I only run one (custom) app on truenas – pbs. I run it this way – Electric Eel - How I am using Dockerfile, .env files, compose files.
However, if I were really serious about running docker containers on truenas, I would probably deploy portainer agent or portainer edge agent (in a VM or as a custom app) and would manage other apps via my main portainer instance, which is used for managing almost all my docker nodes.
Speaking of this, I never tried it (with truenas), but I don’t see any reason why it wouldn’t work. And it may not be the solution you are searching for.