It would be nice to figure out if it’s your ABS system or warped rotors. Can you temporarily take the ABS system out of the equation by pulling a fuse to the ABS system. Then experiment with braking, you’ll still have your normal braking capability, just no anti-lock. If the brake pedal still pulses, it’s probably the rotors. If the pulsing goes away, it was the ABS system acting up. Maybe a wheel speed sensor needs replacing or cleaning.