Krik

Printing the photos won't help much. After 20 or so years they are all discolored. You can't prevent that.

I think SSDs might be the best storage medium for you. Consumer-grade ssds have a 1 year data retention when powered off. That means at least once per year you have to turn it on and copy the data around one time to refresh the cells. This way it'll probably last several 100 years.

You can't exactly make it fool-proof. Outside people will never know what you did to create your backup and what to do to access it. Who knows if the drives file system or file types are still readable after 20 years? Who knows if SATA and USB connectors are still around after that time?
For example it is very likely that SATA will disappear within the next 10-15 years as hdds are becoming more and more an enterprise thing and consumers are switching to M.2 ssds.

Btrfs and zfs are self-healing.

You can make a script to check for errors and autocorrection yourself but that needs at least a second hdd. On both drives are the same data and a file or database with the checksums of the data. The script then compares the actual checksums of the two copies and the db checksum. If they match -> perfect. If they don't match the file where there are two matching checksum is the good one and replaces the faulty one or corrects the db entry, whichever is defect. That's it. It doesn't have to be more complicated.

Any file systems Windows can read out-of-the-box are no good file systems. What Windows read? FAT and NTFS. Former is so basic it has no mechanisms to detect errors and bitrot and the later one is a mess.
You should stick to ext4, btrfs and zfs.

If you want to make if fool-proof then add a sticker with 'bring me to a computer shop to access my content'.

This will do nothing at all. Drives don't die by rust. They usually die because the motor somehow can't get the discs to spin. Very often dry lube is the reason. That can occur if you leave the drive off too long.

For local backups it depends on what you want to have:

• The cheapest option is a usb or thumb drive. But you have to regularly plug it in and copy your backup on it.
• The lazy option is to buy a NAS and configure a backup job that regularly creates a backup. Versioned, incremental, differentials and full backups are possible as is WORM to add a bit of extra security. You can configure a NAS to only turn on specified times, do a backup and then turn off again. This will increase protection against encrypting malware. WORM also helps in this case.
  Or just let it run 24/7, create backups every hour and install extra services on it like AI powered image analysis to identify people and objects and let it automatically tag your photos. Cool stuff! Check out QNAP and Synology or build a NAS yourself.
  A NAS can also be configured to present its content in a LAN by itself. Any computer will automatically connect to it if the access isn't secured by user/password or certificate.

I recommend buying a NAS.

What about OpenMediaVault?
Yes it focuses to be more of a NAS 'operating system' but the file sharing stuff is easy to set up. Any client can connect via nfs, smb or web to access any files.

Arrrr! Welcome aboard, ye scallywags!

In Germany some sections of the Autobahn do double as runways for aircraft. The middle section has a dividing wall that can be removed if necessary. Afaik they are supposed to be used during war. I don't know if they are still being used except to test if new fighter jets are able to land and start again.