The Zeke-5 is a Mid War ride as is the Ki-61. You're still missing the point.
I'm familiar enough with Japanese planes to know that. But I'm also enough of a history buff to know the two weren't natural adversaries, both coming from the same country and all. (Yeah, the IJN and IJA had a bitter inter-service rivalvry, but it didn't ever come to open combat!) I think YOU'RE missing the point that Arenas are STUPID, even though I spelt it out for you... twice now.
The point I'm trying to make is, it's pretty pointLESS to explore matchups that never happened, past a pure similar-vs-similar or similar-vs-dissimilar duel setup. A neutral merge just did not happen that much in the real war, there was almost always some difference in angles, alt, situation, numbers, etc., that totally invalidates the classic duel setup, making it only suitable for "slide rule" type pilots; people who want to quote Shaw line and verse but can only apply it in a rote, specific situation.
The lessons to be learned about energy, position, coordination, etc. are all best dealt with in context of a mission or a situation.... er, unless you're studying HO passes at bomber boxes... oh no, wait, you tend to do a shallow dive into a pass like that, never mind.
What one gets from trying to learn the CONCEPTS, and applying them in combat in many situations, using Situational Awareness skills and playing the cards he's been dealt: that's how you "get good".