secrec
You are correct. But I just wanted to leave the Information here, so the user has all information available to make his decision.
In my option even you plan to run services just locally: If it's not encrypted don't use it (or use it with caution).
But anyway, if you want to use nextcloud and self host at your home you may want to expose it to the Internet. In that case maybe the information I give can come in handy.
Another possible solution to nextcloud is Seafile and run it as docker image for example. But that's for file sync only.