Hartmann is the all-time Ace of Aces. His combat career did NOT begin in Spain. He did’t begin flying combat until 1943.
As to the best fighter? All around? The P-47 hands down. It broke the back of the Luftwaffe before the P-51 came in with the broom and dustpan. It had the speed and firepower to be an effective air to air fighter and of course it excelled at low level work with its ability to haul ordnance. One thing that people forget about the P-47 is that with its turbo-supercharger it performed much better at high altitude where the bombers flew. This allowed it to maneuver with the best of the German fighters and it’s roll rate was phenomenal, almost, if not as good, as the FW-190. Most importantly, the Jug brought pilots home, often with valuable lessons learned.
You are, of course, correct.
Shoulda' used the "Jug"...
Yeah. Often forgotten by many after the war.
The world's leading jet ace -- Colonel Giora Epstein, an Israeli -- had to wangle his way into jets after doing a stint with the paratroopers & then applying to helicopter school because he wasn't considered physically fit enough for fighter training.
Hartmann, Epstein -- gotta be a lesson in there on sheer determination!