Eh.. that’s not too bad.
He is not saying “i’m the greatest” he is just expressing how excited he felt when he realized the magnitude of the discovery- which is pretty huge.
It'll be interesting to see if there's more such texts, unrecognized, in old archives, for example, in southern France (the old Kdm of Arelate, Provencal, Gascony), northern Italy, and the like. It may have been staring everyone in the face, even while the Voynich was getting everyone in a twist.