I had the same problem with my little one. He had always seemed uncomfortable and was tricky feeder, but around 8-10 weeks it started to get really bad. After experimenting with different meds, we ended up putting him on Neocate to see if that helped.
It took a looooong time. We had to wean him onto it from another hypoallergenic formula very very slowly, it was literally a case of increasing it by a scoop every few days.
I kept googling like mad as I didn't see the miraculous 2 week improvement that my paediatrician had suggested. In the end it took about 5 weeks before we noticed a difference.
Since then, my LO has really come on, he has suddenly zoomed through his developmental milestones and he is like a different baby, but it wasn't overnight but actually quite gradual. He downs his bottles in one now, and you know that when he tells you he's had enough, that he is actually full and you don't have to try and persuade him to take more.
We have even taken him off the omepezrazole (very slowly) and infant gaviscon.
I have since started weaning and it's definitely not the magic answer - some foods seem to bring back his reflux, and it's a nightmare trying to wean a baby without being able to give him any dairy. We are doing baby led weaning and I would definitely recommend this for babies in this situation, as they seem to instinctively know what they want and don't want. He had oral aversion already, so trying to shove a spoon in his mouth before he was old enough to fight back would have been the worst thing we could have done for him.
So hang on in there, take it VERY slowly introducing the new formula, don't expect results for another few weeks and I definitely, definitely wouldn't even consider weaning him yet, as you could make it worse.
Good luck, you have my sympathy.