First of all congratulations on your new baby!
Second of all I'm sorry to hear that she's only barely arrived in this world and her parents are about to break up. That's really too bad.
Thirdly, you say that you have been thinking of names for months, you suggested them, you've had a list, that he refuses any of your suggestions, refuses any of your compromises, and it's less that he wants to pick a name that he likes for your child's life and more that he just wants to block your favorite choices. This is probably one of the many many reasons why you guys are facing divorce.
Is it fair to say that you grew the baby, you gave birth to the baby, your nursing the baby and caring for the baby so you should get to choose the baby's name? Well, who cares? What in life is fair?
The naming issue sounds like it's probably just one on a very very long list of grievances as to why your marriage should not continue. If you were able to choose hair or eye color, I'm sure that he would be blocking your choices on that as well. It sounds like he's just being argumentative for the sake of it, and the sooner you begin divorce proceedings which I am very very sorry especially because it has to happen at this time when you have a newborn, probably the better.
If you're probably going to be the main parent, hell, you get to pick the name. It's not that he's got his heart set on a particular name that means so much to him, you said he's lazily used chat GTP for a list, and his main motivation seems to be in preventing you from picking your favorites. F that noise. He's an a*.