I don't think your concerns are founded, I just deployed GitLab for personal use on a virtual machine with the omnibus image (gitlab-ce:latest) and it worked flawlessly. And since they released an update today, to upgrade all I had to do was:

    docker pull gitlab/gitlab-ce:latest
    docker stop gitlab
    docker rename gitlab gitlab-old
    docker run --detach --publish 60100:80 --publish 58432:22 --name gitlab --restart always \
         --volume /var/volumes/gitlab/config:/etc/gitlab \
         --volume /var/volumes/gitlab/logs:/var/log/gitlab \
         --volume /var/volumes/gitlab/data:/var/opt/gitlab \
         gitlab/gitlab-ce:latest
    
    # after verifying the new image works, docker rm docker-old; docker rmi [old image]. 

It took less than an hour to configure it for external SMTP relay, external auth with two factor authentication, etc.

I did just get started with it, but I have to say the omnibus install was fairly easy.