not everybody who sleeps on their back snores and can't breathe?

Surprise, surprise, people are different to each other. I pretty much can only sleep on my back, no other positions allow me to fall asleep. Also, I don’t snore.

But I’m also very much in shape with no excess weight, snoring is generally correlated with ill health and being overweight.

I'm an expert snorer and can snore in any position. Probably central apnea, which only activates when most comfortable; previous sleep study showed nothing, presumably because I wasn't totally comfortable. I'd self medicate with a cpap if they were sold without a prescription. B1 with dinner/before bed helps, oddly.

Also, my previous cats preferred to sleep on my chest, so they trained me to sleep without a lot of motion. Currenrly, one cat likes to sleep on my legs and overheats them, resulting in a lot of movement at night; the other cat will only briefly visit at night, but will help me stay in place for naps on the couch.