I recently saw this study, but it's almost 20 years old, I don't know if there's more recent data available.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1360393/

"Didgeridoo playing as alternative treatment for obstructive sleep apnoea syndrome: randomised controlled trial"

When my band toured and we could afford two hotel rooms, the singer would get one room and the rest of us would take the other. He was by far the loudest snorer of the 5 of us. Obviously just a funny anecdote but definitely not always the case that singers are the quiet sleepers. Or maybe he just needed more singing lessons.