Soy formula?

I do have an appointment with my son's doctor in the morning. But looking to see what others opinions are. We have tried everything for my little guys gas and fussiness. I have tried 5 different kinds of formula. Some he will just flat out refuse to take. And others it doesn't to seem to be helping the gas or fussiness or even makes it worse. He currently is eating neosure and similac pro sensitive. He was a premie then got really sick with RSV and lost weight. He was getting half breastmilk, but lately has been refusing those bottles and has been eating better with just formula. We have tried Enfamil gentle ease, Enfamil reguline, similac alimentum, and similac total comfort and gerber soothe. The combo he is on right now is literally the only thing I can get him to even drink. He is on reflux meds to see if that's part of the issue. They seemed to help right away. So I think the next step we might need to consider is soy formula. Thoughts? Best one to try? I just want my little guy to be comfortable and happy. He screams most of the day 😢