Dude, we get to see into griffith's mind during the year when he is tortured in v10. He flat-out recognizes that the only person he ever gave a real shit about was Guts. Isn't something that's really up for debate, for it is explicitly stated. And yet the sacrifice still worked. From that we can extract that what matters is the willingness to offer something as a sacrifice, and not whether the sacrifice actually happens.
As for how he saw the hawks... add his speech to charlotte about how he doesn't see his followers as friends + willingness to kill that which he can't have + trying to fuck casca to reassert ownership as soon as he realized he lost her.
Dude cares about them in the same way that a slave owner cares about his slaves.
You weren't paying attention then or else have forgotten it. He didn't say Guts was the only one who he cared about, he said Guts was the only one who made him forget his dream. Big difference.
The look into Griffith's mind played out roughly like this: Griffith is playing with other kids when sees a castle in the sky and wants to get it. So he goes after it, and his friend is there....except he realizes that his friend is dead. He's dead because he followed griffith in trying to achieve his dream. Not just him, because Griffith is surrounded by hundreds of people who died in his name. Griffith is horrified by this, but then one of the Godhand reminds him that this is what he wanted and that if he turns back now, all the people that died for him will be for nothing. Griffith acknowledges this rationalization, and puts on a determined face, and throws the body of the kid onto the pile, because that pile needs to be high enough to reach the castle, because if he turns back now, then....
And that's griffith in a nutshell. He cares for them, but he really doesn't want to, so he rationalizes himself as a pure ends justify the means utilitarian. His explanation to Charlette isn't how he honestly views things, but rather the kind of perspective he falls back on when the guilt becomes too much, because he wants to be this cold, callous, uncaring general that is just using his pawns as tools but at his core, he isn't. He's cultivated his entire personality on that archtype, but it breaks in multiple ways. For example, Griffith had to sleep with a count to get funding for his army. As much as he tried to just think of it as a cold exchange of sex for money that was perfectly logical, his actions at the river Caska found him him, tearing his finger nails into his own flesh, showed that he feels violated and ashamed for the act of prostitution that he did. So, griffith cares about them as people, but
wants to only care about them as a slave master cares about his slaves. Because if he allows himself to acknowledge and indulge in that kind of view, then he similarly has to acknowledge the mountains of dead behind him.
What Guts did to rock the boat was make him forget his dream in the sense that he got complacent. That's why his imagined life with Caska after he got crippled, one in which he was actually satisfied with, was there. Griffith cultivated his entire personality around persuing his dream with a singleminded determination, and Guts was the only one who made him think "You know...maybe if I didn't get that kingdom, life wouldn't be so bad". It's true that Gut's is definitely the one he cares about the most, because he saw him as an equal. Guts is atleast as extraordinary as him, but he kept trying to think of him as lesser, which is what prompted the episode where he lost to Guts and then slept with Charlotte, leading to his imprisonment. So when he realizes the fundamental affect Guts has had on him, like any unstable individual, when he realizes that the illusion of personality he's cultivated is shattered, he reacts badly. He blames Guts like he violated him somehow, by making him forget his dream, because he so very badly wants to be a monster and isn't one. So he makes the sacrifice required, and truly becomes one as Femto.
Furthermore, if we take your interpretation as true, then Griffith's ascension makes no sense withing the rules of the Berserk universe as we know them. The way the Behilits work is one of the first things established in the story. In the Blackswordsman arc, the Sluglord tried to sacrifice Guts, but they wouldn't take him. Godhand only take what is sacrificed and the only thing that can be sacrificed is loved ones. That's why they didn't attack Guts, not even when he tried to attack them (which he failed because of the mark). Sluglord didn't care about Guts and the Godhand laid out that the only way it works is when you sacrifice someone you care about. In that scenerio, only his daughter qualified, not Guts. So, since Griffith sacrificed everyone
except Gut's and Caska, if you're interpretation is correct, we have a giant plothole around the event that the entire story hinges on and literally the entire story makes no sense.
