I am not sure what are the conditions/benefits provided by MetaARPA level, but my guess is that any NC access would be provided only to your specific SDF account, and with limited space/bandwidth.

And if you plan to offer family/friends with access... Well, I wouldn't want auntie Alice to see uncle's Bob backup folders and say "oh, I don't need any of this crap, I will delete it so @jdh knows how a nice user I am".

Save yourself some headaches and consider the basic plan from hetzner (https://www.hetzner.com/storage/storage-share), and just create a user (with quotas!) for each member that needs access. The service literally takes care of everything, and you only will need to remember to check that your apps are still properly enabled after they perform any updates or maintenance (and they will be perfectly fine 99% of the times, with the other 1% just requiring you to click on enable/update for some specific app).

Learn from there and then you can grow to bigger plans or, if you really feel the need to it, go full ahead hosting your own instance (maybe initially a cheap droplet in digital ocean, or a compute instance in scaleway, so you can learn the basics and break things). Next level? Pick a bigger instance or one of the real servers from hetzner's auction and go nuts. But always remember: auntie Alice won't be happy if your tinkering risks her collection of funny cat pictures. Always keep a backup of the backup (and test that it works!)

Always consider that just moving into nextcloud gives you much more control over your data than with any google/microsoft/somethingsomething service, since you can always just launch another nc instance anywhere else and move everything there. But at the end you ALWAYS must trust someone (your providers, your vendors... your users) and if you REALLY are paranoid about some unauthorized actor accessing your information, then self hosting in your own dedicated hardware is your only way, and that costs time and effort.

Regards!