So thinking this through, your best bet long term is going to be a multiple cloud back up system. Its probably more than you would want to pay, but they’re already digitized. Its not crazy to just take advantage of what these kinds of systems are good for, which is distributing backups across multiple servers.

But having local backups is also important. Thinking this through, one cost effective option would be to first back up the CDR to hard drive, for whatever machine you have. Then, burn multiple copies of the data to CDR. Make 10 copies. Send five to family members. Take the other five and shove them in the same place you archive your other stuff. One CD can absolutely rot/ fail. But its unlikely that all of them would fail. If you store them properly, in reasonable house hold temperatures, and you aren’t constantly reading or writing to the disk, they should just kinda sit there and be fine.

If you have a burner, if you want the least technical cheapest approach, thats what I’d recommend.