How is a backup into the cloud or hard drive is a sub-optimal solution.
There where the MO-Drives, that really lasted many decades, but they also vanished.
Best solution currently are the old-school tapes, since they are created as real backup-solution. Trouble is, that when you want to buy a current drive (with enough data density) you will have to invest a stack of money just for the drive. Also the equipment and tapes are seldom sold for consumers. I looked up some figures ... and one cartridge currently costs half the sum of the same hdd space (consumer drives). So even the cartridges are rather costly for consumers.
Hmmm, and it looks like MAM-A Silver and Gold CD-Rs are what we're going to have to switch to. Previously they weren't judged as really needed given the quality of Taiyo Yuden CD-Rs, but if the latter aren't available....