What you could do instead is write down idiot proof guides on how to access things from mac and windows, write down passwords, tell them how to access ntfs from Mac and vice versa etc.

It’s what I’m doing. Only bad thing is that you have to update it every once in a a while because things change.

How much TB do you actually need? Such a long post…

I like synology for simplicity. And because I believe it‘s hard to get proper alternatives for synology drive and photos

Actually USB-C could power it. Or at least some ports could. But USB-C is a clusterfuck hence…

Because 5TB has been the maximum for ages and isn‘t really all that useful

Id get a synology with two bays and then use shr1. I think that the „synology drive“ app might work well for them. It will sync each users data to the /home folder the syno NAS.

Then you make sure to get btrfs compatibility so that you can use snapshots, get snapshots for at least a year or more if we’re talking about small files.

Then use hyperbackup on the NAS to automatically backup whatever is important to the cloud (i like hetzner storage boxes but synology c2 works as well) AND to the external disk they are using right now.

Snapshots will protect from accidental deletion and malware encryption. Same for the external disk mostly. The cloud backup will protect from all that + fire, theft etc.

While synology drive sync works wonders, the local devices won’t keep a full copy, so keep that in mind when using it since that won’t count as a backup. And your folks have to be instructed to put stuff only into that synced folder or it won’t backup at all.

That way they never have to worry about manually backing up or even using the NAS at all. However, the Nas has to run for this to work properly.