A raspberry pi is not going to be powerful enough to run these things beyond a test setup or, a really small use-case. I'd only setup #Nextcloud with the SQlite setup. And don't plan on using it for mass storage. and for heaven sakes keep a backup. :shiba_please:
That said, if your goal is simply to run these out of your home and you want to access it beyond your intranet, all you would need is a VPN back to your house.
Avoid openVPN :openvpn: Simply because it's a resource hog, albeit the more reliable option. Wireguard would be better especially considering you're already going to be bottlenecked by the pi :raspberrypi:
I don't know much about Podman or Quadlets. But, a Docker instance will work just fine. :docker:
Updates are not too tricky in my opinion. I can share my own update script for my Docker Nextcloud setup if you want. It'd probably be adaptable for jellyfin and whatever else.
Just make sure you expose the Nextcloud data directory as a volume outside the container. and before you back it up always try to update so that if you have to reinstall you'll have a better chance of having a compatible backup.