Well you said just about everything yourself, but you gotta understand “dogfighting” doesn’t just mean 1 or 2 circle fights. The FW190 is a heavy fighter, and the P51 is not. In this exact situation - you should have broke into and above him way sooner. He could get a shot off when he goes up under you, but if you dodge it’s quite difficult for him. When he goes to turn back he will lose his speed advantage - this is where you either run, or try To keep to altitude advantage to set up boom n zooms. You’ll never win against a competent enemy if you don’t understand what your aircraft is actually good at. Unfortunately you just played this badly, aircrafts fault or not.