Thanks.
Careful, this is not a tutorial, your mileage may vary. Typically, what the story doesn’t tell is that I got a 2nd similar bitflip in that same backup/snapshot later on. In that 2nd scenario, it was the last out of 4 blobs again, but it wasn’t starting at the beginning of the file, so I had to truncate the reference file with a skip option after identifying the correct offset (which I did simply by searching a binary string).
Just make sure you understand every step.