Help! Major spit up after every bottle

Hey mama’s - need some advice.

My baby has spit up more than average since the day he was born. I’m not starting to supplement with formula (he gets 4 formula bottles and 4 breast milk). I’ve been noticing a trend that he spits up way more after formula bottles (up to 12 spit ups in a 2.5 hour span...most of them are large amounts of spit up). I’ve called the doctor multiple times but they don’t seem concerned...he is now 4 months and it seems to be getting worse (more spit up, more times). We burp him half way through and after (he gets 3-4 oz a bottle) Usually when spit up happens it is not accompanied by a burp...this is the second formula we are trying. We started with enfomil gentlease and now are using enfomil espire. Has anyone else had a kiddo like this?! Did anything work to help it? I thought it was suppose to get better with age..stresses out mama over here