It was really an open and shut case for involuntary manslaughter. The other two charges should be appealed and thrown out.
Regardless of a perpetrator's level of cooperation you can't use deadly force unless you feel your life is in danger.
Regardless of a perpetrator's health you can't do something that is negligent in regards to that person's health.
If the perp is having a hard time breathing because of poor health you don't place your knee on his neck. I am also pretty certain his academy training didn't involve knees on the neck restraint.
A neck restraint is not deadly force. And no, Chauvin was not able to detect Floyd's multiple heart conditions and drugs in his system that lead to his heart stopping. He was saying he couldn't breath while the cops were trying to get him in the car, nobody is going to take those claims seriously.