When I took charge of solving backups for the single important box with unique, irreplaceable data -- the accounting system -- at an SME a long time ago, I think I approached it with the right amount of correctness. Therein, losing a day or three of recent data would have been recoverable; losing all of it would have been catastrophic.

I devised a system to perform bare-metal backups onto an easily-swapped, external 2.5" hard drive, using Acronis. I provided a plurality of these hard drives, and they were to be rotated off-site. The system was tolerant of human error and would proceed with making valid, current backups even if the drives were rotated incorrectly, or if not rotated at all on any given day. The backup drives each had complete file history (yay shadow copies) from an ever-advancing date, so any given drive could be used as a time machine of varying resolution, and also as the single source from which to independently start fresh.

I'd watch the logs to see that it was done, and for the most part: Whoever was assigned to that role normally did it properly-enough.

I documented it and showed the other technical folks how it works.

Sometimes I'd wander back and make sure the backup drives weren't accumulating on-site (there should never be more than 2 on-site). I'd periodically test these backups by restoring them completely onto identical hardware, to make sure the system hadn't got crufted up somehow and that it still continued to perform its task of restoring a working system from zero.

It worked fine for years and years. We never had to use that backup, but I had every confidence that it would be useful if that ever became necessary.

Eventually, my role changed and those things rather officially became Not My Problem.

Later, they moved the accounting system from that lineage of stout Proliant boxes to a trash-tier small-form 1u Lenovo machine that someone found used, on eBay, for cheap.

Backups are handled by the clown, somehow. The last I heard anything about it, the person doing the talking was very pleased with the money they'd saved and that they'd no longer have to pay "extortion" to Acronis.

I have every expectation that nobody has ever restored these backups. They're probably relying on the sheer hope that they'll never have to restore them, much less from zero.

And I also hope they never have to restore them, lest they may find out exactly what that data is worth to them.