Also, your airway and trachea are in the front of your neck not the back. While kneeling on the back of the neck will be painful, it will not cut off the airway, hence this being a long standing method of subduing a perp with no deaths as a result.
Couple that with the fact that he was almost immediately saying he couldn't breathe (aĺl the while talking), establishes that he was going into cardiac arrest due to the drugs in his system as the scene unfolded.
Also, Chauvin knew he was being recorded and had a crowd of witnesses. There is no way that this LEO would have performed an act of any kind that would lead to death with literally all eyes on him.
This case, like many others these days is racially motivated and anti-cop. Hallmarks of the woke society.