Here's generally a good G4 fight:

As the fight starts, shoot a few of his eyes with the minigun. Walk a bit backwards and throw a grenade so it detonates as he lands in front of you. Once he's in front of you, knife him 2-3 times with the intent to knock as many eyes as possible. If done right, he'll instantly go to climb. Wait for him to start the climbing animation, and then throw a grenade.

When he's knocked down from the wall, knife him 1-2 times again making sure you pop eyes. If you're too slow getting away, he will swipe you. When you're running from his swipe, he will regenerate enough eyes for your grenade to deal max damage. When you're a decent distance away, throw the grenade, and finish the fight with the minigun.

The entire fight is based of how many eyes are being popped, so spamming knife and grenades when his eyes aren't up wastes time.

thank you, sir! I've been trying to figure out boss mechanics/damage. I only got a consistent G1 fight so far, need to practice the rest of them. trying to run claire hardcore 60fps

Very helpful thank you. Doing 60 FPS Claire, any more suggestions for G2 And G3? I also got G1 down easy but need more consistency with the others.

I don't think there's much we can do for G2 since it all revolves around maximizing damage within the time frame of the crane setting up. Kind of unfortunate, but I think that's reached it's limit lol.