i dont want to derail but, the best fighter aircraft in ww2 was the fw-190 series. they had the most success
Can't gauge it that way since we are talking about different factions with assymetric balance.
The FW190 operated in a much more target rich environment. While Allied fighters later in the war seldom had targets other than other fighter to shoot down, the German fighters had a sky full of large and medium bombers, recon planes, possibly even transports doing airdrops, slower (and distracted?) Soviet ground attack planes.
German Aces also benefited from the German Ace syndrome were a "star" pilot was going to get the benefits of the doubt in the case of kills as well as when it is being determined if they made the kill or someone less famous.
Airplanes are not machines, they are "weapons systems". The FW190-A was an inferior plane to the P-51 in all but low altitude combat (which rarely happened with a P-51. The Dora-9 variant came in the fall of '44 (so it is a year or more newer than the P-51D) but at best only edged out the P-51 in high altitude performance by a bit. But the German pilots at this time were of much poorer quality. And even had they been the equal of the allied pilots, they were by then almost always vastly outnumbered.