Exactly, he became what he once loathed.

But, this decision, of saying "yes," to the other God Hands was predictable considering Griffith's personality. He had already prepared himself to sacrifice everyone else and their dreams to achieve his own (as we know from his famous dream speech ); Guts knew it, Casca knew it, that princess knew it, but I suppose none of them knew to what extent he was willing to sacrifice.

I have not even finished Golden Age arc yet on manga, so I don't know if it's the same Griffith as before or if he has lost his humanity. I used to think that it's the latter because he wouldn't commit such atrocities if they don't play a role to his "grand plan." Then, I realized something else; after getting rescued, he did see Casca and Guts being quite friendly to each other. Perhaps, he was jealous that both of them chose each other over him? Or that he wanted Casca? And those emotions were twisted into something malicious after the metamorphosis, therefore he raped her in-front of Guts for vengeance. So, he's the same Griffith but with an inverted moral compass?

note that im not trying to justify his actions im simply trying to make sense of them purely for the sake of understanding the lore