You are correct. However I think in practice you can get away with it if you keep bandwidth low. I've been running a OwnCloud/NextCloud server from my residential Comcast account for years with no issues.
Meanwhile, I installed backblaze on my home machine, which started backing up around 500gb of my disk, and summarily got a message from my provider that outbound traffic of 30gb is an ‘inconceivable’ amount of traffic during normal use, and if I could please stop, or else (lawyers).
I wonder what happens if nextcloud does a full sync to a new device.
What provider? That behavior deserves a name-and-shame.
As far as what happens with a full sync: it's not really doable outside of the LAN for several reasons. One is I have a data cap from Comcast of 1 TB/month. Another is the upload speed is only 10 Mbps. That's actually one of the reasons I went to self hosting.
