Yeah i use a synology for that. my public nextcloud has like 250GB of storage, which is plenty for 4 people to use it for photo backups and whatever else. If i need access to some random file on my network, i use tailscale - there are other options. i could buy/build an ipv6 router and use prefix delegation to get a public ipv6 on my synology.

You're looking for storage. Not sync. the clue was "terabytes". Wanna know where i draw the line? you can't sync terabytes to a phone.

I'm not trying to sound like a jerk. All of the things we mentioned are software based airquote "storage", dropbox, syncthing, etc. your original thing was "shared a folder with SO" which is why i asked what the folder was, mostly. Matrix will gag encrypting a TB of data. Misskey's drive defaults to like a gig per user.

Get a NAS, tailscale (or whatever, set up your own VPN with a fortigate or something), and now you rely on no-one but your ISP(s).

Proof that this works, just fine: https://imgur.com/a/q9hLDeH

note: I use both nextcloud (with a real domain name and certs and everything!) which is a VM on one of our machines in a DC. the synology is at my house. The synology backs up to a dedicated machine (it's in an air conditioned outbuilding with dedicated fiber pulls) with it's own redundant storage array, but that machine is "asleep" 99.9% of the time unless i'm pushing backups. My synology is not publicly accessible. It has ~30TB of storage, iirc.

note2: that youtube-rips is 90% <=480p, too!