100% everything here. That level of tamper evidence should be good enough for the reasonable individual, IMHO.

On the enterprise scale, the question I think everyone should be asking is: Do they have LTO tapes on a shelf? Fundamentally the same issue (but larger), in terms of needing to ensure it's physically separate, and secure, and tamper evident. =)

Anything in the cloud or connected to your network can be hacked. The backup of last resort must be on a shelf.

This seems a little over the top to me.

Just use a magnetic hard disk and your data will be fine for many decades if not centuries. You don't need M-Blu Rays (which have very limited capacity anyway). A hard disk is cheap and stores several Terabytes.

You obviously need to store the data in a physically remote place like your shed, car or safe deposit box in case your house burns down.

Never, ever use a SSD if you want your data to be safe for any amount of time. What's worse, SSDs can fail unexpectedly with almost zero chance of data recovery.

Are Verbatim's M-Disc Blu-Rays still really M-Disc? There was something about how they changed the recipe a few years ago, and the counter-argument was that Blu-Ray discs are non-organic anyway, which was the main feature of M-Disc DVD.

I debated doing this recently but ultimately spent a lot of money on an LTO-6 tape drive instead, just due to the cost efficiency over time for larger amounts of data. I justified it to myself as I needed to either expand my NAS or clear stuff off it, and the drive was the same price as buying two new HDDs to expand the NAS thanks to the obscene price inflation at the moment. As I’d likely need to further expand my NAS next year (I’m shooting a lot of photo and video) I think this works out a much more cost effective way of storing this data long term when I likely don’t need to access it much.

Now that I'm at ~$350 a year on Backblaze I need to look at this again. Or the LTO-6 tapes.