Brakes will always overpower the engine unless the braking system is severly damaged. This is simple physics. Cars decelerate far faster than they accelerate, which is to say, the brakes can generate far more horsepower than the engine can.

(Apparently the Rimac Nevera, with about 2000hp, can accelerate faster than it brakes. So that one might be the only exception. So unless you're driving a 2000hp car, the brakes will always overpower the engine, that is not debatable.)

Brake fade is irrelevant here. Brakes fade when overheated beyond their operating range, either due to fluid boiling and/or the pads overheating. This is nearly impossible to achieve in street driving, but can be experienced on the race track. None of the claimed acceleration accidents involved extreme repeated braking prior to the incident.