Took me a weekend
First run:
docker compose run web bundle exec rake mastodon:setup
This will guide you through the setup. Remember that without SMTP mailing setup, you can't create new users, so only an admin user will work.
Copy the values created in the setup guide to the .env.production.yml file.
sudo chown -R 991:991 /srv/mastodon/web
commit the changes, push to repo, start the container
docker compose up --build
This should just spin up the container.