It will probably be best for you to pop into discord for support. I will note that we do not support or recommend deploying our containers with portainer. It also looks like you are using a remote mount for /config, we do not support this either. Finally, your docker version is CRAZY OLD and there have been a ton of critical updates since your version was released in June of 2021.
This is because you checked the uid/gid incorrectly inside the container, you went in as root, so you saw root. docker exec -it -u abc jellyfin id $whoami