Brakes not working after bleeding and new Master cylinder/booster

I recently installed a new master cylinder and power booster, and one new set rotors, one set of new bearings, one set of new calipers, and 1 set of new brake pads on the front brakes for my vehicle. I bled the master cylinder, and bled all the wheels in the proper way. Bled each wheel eight times in the correct order from farthest to closest to the master cylinder. I also used a clear tube immersed in brake fluid to watch for bubbles, and a partner pumping the brake. Kept master cylinder topped off, and bled each wheel until no more air was coming out of the lines. Pumped three times, on the third time, partner held, I loosened bleeder valve, then shut the valve before the brake pedal stopped moving down to the floor.

My problem is that the brakes still do not work. I noticed that when I am not moving or only edging forward, I have a mostly solid pedal and the brakes work. However, as soon as I start moving at driving speed the pedal loses pressure and goes to the floor. Do the lines need to be bled again? I cannot imagine there is any air in the system.

I also checked the power booster for the right adjustment length on the push rod, and it is correct. However, when I put the master cylinder back on, it seemed like the booster was not working as well either. Everything was put back the way it was found, but now it seems like the pedal is harder to push. There are no vacuum leaks in the booster. I checked. What is the problem here?