My LO faces the same and we haven’t figured out a proper solution. But a few things that work sometimes are laying him flat when is trying really hard, feeding in an upright position (that seems to help with the pressure). Trying to burp after a break and when they are less resistant. You could try a rectal stimulation with a warm cotton ball (soaked in warm water). For us, we would try all of these until something or time worked.
These drops have helped my LO! Reflux + stubborn burper https://amzn.to/4isfbhA
I use gas drops several times a day for gas and we did a formula change as well if you’re formula feeding. Now we get him to pass gas but can’t get him to poop unfortunately.
My pediatrician recommended immune +digestion support drops. It’s a probiotic with vitamin D