Please NEVER use SETUP=true for worked node, you may destroy it! The setup step should be executed only once for entire node’s life.
So you must skip the setup step and use the next run step.
Yes, that’s right but use for normal docker run without SETUP=true.
The one instance of watchtower is able to update multiple containers, just list them, i.e.
docker run -d --restart=always --name watchtower -v /var/run/docker.sock:/var/run/docker.sock storjlabs/watchtower storagenode storagenode-2 watchtower --stop-timeout 300s
your user and group, i.e. it will likely expand to --user apuokas:apuokas, this is also mean that you need to configure your docker to be run without sudo and data location should be recursively owned by your user (not root). Or you may remove this option and run it with sudo (in such case data location should be owned by root).
To run multiple containers many uses docker-compose, for example: