to latch baby for 1-2 hours can be too long for 3 weeks old baby. That’s why will vomit after burp. Baby may feel too full Usually recommend to latch max 20-30mins for both sides every 2 hr or latch 10mins then bottle feed Breast feeding milk flow can be fast / slow. Maybe you can try cut down and observe. Also do check whether has colic issue
Is he latching well? My #3 was latching for 2-3hours each time and all he does was to puke the milk out in the end. Although his growth was normal, I ended up calling the LC over and realised he was lip tied that’s why he couldn’t latch well.
Rae