2011 Toyota Corolla Brake issue

I have had issues with the brakes making a noise when
going down hill at high speeds(60+mph). The brakes
sounds like a vibration almost shaking the car but not.
This has been going on since we bought the car brand
new. I have taken it into the dealer about 6 times and they
say there is no issue, or that the rotors are warped. I have
had the rotors replaced, brakes replaced at the dealer
many times and the issue keeps coming up. Over the last
couple years the brakes continue to do the same thing but
now they are also making a screeching noise when
stopping like I need new brakes. I again replaced the
rotors and brakes but this time with drilled/slotted rotors
and ceramic brake pads. I have had them on for about
300-500 miles  and the sound has not gone away. The
dealer continues to say it's driving habits but it is not
possible with new brakes/rotors time and time again with
the same issue occurring almost immediately. Any advice
is greatly appreciated.