Quite clearly NO It is a central office that now answers a large part of the DNS questions; apart from the fact that they so often have failures.

you only have to start a second docker cluster with a different public port

From the moment I read Cloudflare, I was out.

thanks for the help, that put me on the right track, apparently an old image was used.

I always thought that a docker-compose up -d also builds a new image. But apparently I have to run docker-compose up --build -d. thanks for the help

I’ve been using nextcloud for years without any problems

I would clearly prefer Proxmox, which gives you the greatest possible freedom in terms of what else you want to do. Then a VM or LXC for each service.