‘I’m writing this not as the prince I was born but as the man I have become.”
Or as whatever my wife tells me to be.
Exactly
If Harry the Viper wrote that sentence, it's clear he doesn't know his native language's correct grammar. Also, the whole of a person's life experiences shape the person we are at any given point in our lives. Harry is who he is because he was born into great wealth and privilege, exempted from the consequences of almost all negative behaviors as a child and young adult, and had the benefit of being treated as a royal all his life -- yes, even now. The truth is that he is a rotten, spoiled brat of a human being who doesn't grasp how extraordinarily lucky he is.
“but as the man I have become”
a pipsqueak of a man worn down to a nub?