The initial Coronors reports said he died of an overdose, It wasn't until the family paid for an "independent coronors report" that they came to the conclusion that he was "murdered".
Have someone kneel on the back of your neck, I can tell you from experience you can breath fine. I was in a bar brawl many years ago and I was restrained by a cops and he knelt on the back of my neck , dude had to been 300lb, twice what that skinny cop weighed that pinned Floyd, I could breath fine.