N1K1 Kyoufu silently siting in the corner and hoping nobody remembers him because he sits at the same BR, can break of his floats to and trades a littel bit of agility for more 20mm ammo and got almost 500PS more engine power then his Zero cousin.
Personally i have no problem with them at 2.3 and if you know how you can still beat them fairly easy.
And like mentioned before, even breaking the floats of can be challenging (high risk, high reward).
If i would to name a broken Plane for BR 2.3 it would be the Mig-3-15(BK).
Very fast for the BR, very heavy armed with 2 7,62mm mg and 3 12.7mm mg all in the nose and a airspawn.