Recreating iCloud

Hello guys

I'm currently planning to recreate iCloud as I'm paying roughly 36 Euro a month for Apple+ family plus 2 TB of storage and all we're really using is the storage. I could get an external 2 TB Samsung S9 SSD atm for 170 Euro, so including power and a little extra for an Indian (or whatever) Spotify subscription it should pay for itself in less than a year.

I'm running Unraid on my home server with a NextCloud Docker container that I haven't really touched yet. In my understanding, that would be a good and very easy base.

Now for the (at least for me) harder part: replicating or mirroring the storage in other locations. I have family members from three different households using my family storage and they all need to get access as well. I would buy the same external SSD for all of them to run it locally which should be enough in terms of backup I think. My question is: what do they need in addition to the hard drive (and regular local network infrastructure) to make it work? Would it be enough for me to also provide a pre-configured Raspberry Pi 4 with a NextCloud docker container and a WireGuard client that they basically just need to plug into the ethernet port of their respective routers? For some of the (older) folks the set-up would need to be as simple as possible, also for techsupport over the phone.

Thank you very much for your input!