please help choose formula

Anna • I am 26 year old happily married woman. I love reading, traveling around the world, pets, music and so much more.
Our doctor is a big enfamil fan. We tried and gentle ease and prosobe. However, AJ spits up pretty a lot and can be really gassy and fassy. ( he is 4.5 months) I want to try something else and see if that helps and keep him calm and happy. What is a good formula to try? What works for you? And what helped you in a similar situation? Thank you