Pressure on the SIDE of the neck - which is what that method of restraint does - would NOT cut off the airway, UNLESS the pressure was so great that it would cause damage and NO damage was reported.
Sufficient pressure on his BACK, on the other hand, WOULD have prevented him breathing, which COULD have had the fatal effect you mention. Perhaps you know for how long the black cop was on Floyd’s back (see my posts 21 and 51).
The entire event is available for free viewing in a documentary called ‘The Fall of Minneapolis’.