Encrypt it? There are some strong algorithms that allow you to enjoy the most highly secured, fault-resistant buildings on earth without letting the capitalists that own them view your data even if they were to hook your storage up to their entire GPU/ASIC/etc farm.

What if your house burns down?

i keep a copy of my most important files in a safe deposit box

I keep my FLAC collection in a safe deposit box. More important files get stored on HDDs and MLC flash. Storage is cheap.

Nothing stopping you from putting NextCloud on a Raspberry Pi

I don't know about the mac, but I tried to do this for the wife/kids i-devices, and it was an utter failure. 3rd party backup apps are at a huge disadvantage on ios because apparently they can't run in the background long enough to keep things synced unless they also require _GPS_ service notifications (or at least that is how the nextcloud app works around it). Which in turn eats even more battery to work around ios's inability to flag apps as trusted system services and provide extra warnings/whatever during install (or app store acceptance might be a better plan).

> or

There was another simple option. You're free to use that one.