It occurred to me the other day that Japan doesn’t have a fighter in BRIII. Just a quick bit of research suggests that one of the variants of the J2M “Raiden” might fit the bill. It is slightly better armed and would likely be slightly tougher than the A6M2.
Update: and I’m dumb. The J2M3 is BR5. Probably shouldn’t make suggestions at work. That said; that isn’t the only variant. Although with the climb and turn rate it has… I don’t know. I’m just dumb.