Some times it helps to lie them flat on their back, let them kick their legs for little bit (2-3 mins) then pick them back up and i found they brought their wind up easier then x
We struggled to burp our grandson when he was first born. One way we got his wind up was to sit him on your lap with your legs slightly apart and his bum in between your legs rather than him sitting as he’s not scrunched up. Another way was to sit him facing us on our chest but we didn’t do this until he was holding his head up on his own. Or you can try standing with him and jiggle him a bit. Another way a nurse showed us was to hold him face down with him stretched out down your arm and tap his back that way x
My LO is 4.5 weeks and still have the same issue. Infacol helps but not that much