General docker implementation

Hi.

I have a general docker / network setup question.

This is my starting point:
1st computer: RaspberryPi with installed PiHole and docker on top.
In docker (portainer, heimdall)

2nd computer: x64, with OMV5 and docker on top.
In docker (portainer, linuxserver/nextcloud, mariadb, myphpadmin)

Both systems are up and running.

What it want to do / what I want to have:
-> Access to Nextcloud from my domanin cloud.xyz.com via https
-> easy way to update my domain with new subdomains and maybe OMV or something else accesible from outside world, reverse proxy? Don’t want to add the port to the domain when opening in browser
-> automatic ssl certificate update
-> https access to my “sites” in local network
-> 1st computer is always runnig and online. Later, I might want to disable the 2nd computer and want to have still access from outside world to my hosted sites on 1st computer.

What about the approach with “Caddy Server” or “linuxserver/letsencrypt”
To different solutions within the docker
Which one would be better? Or something else?

Thank you in advance for your support