I'm not sure he did either. Intent isn't required for a charge of 3rd degree Murder under MN law:
"without intent to effect the death of any person, caus[ing] the death of another by perpetrating an act eminently dangerous to others and evincing a depraved mind, without regard for human life"
Chauvin was told twice that Floyd didn't have a pulse. If your next action after being informed someone's heart has stopped is to continue restraining them instead of administering aid, you were more interested in them staying dead than recovering.
I'm not saying it's a slam dunk but his actions on the day very much open the door for 3rd degree murder.