Could try burping more & more frequently during feeds :) my little guy (5 weeks) vomits & gets hiccups if he’s not burped enough
I think it is more likely to be reflux if baby is projectile vomiting rather than just mouthfuls of sick up. May just need burped or paced a bit more. Would try that before changing any thing you are giving them x
Our girl is six weeks old now but she has silent reflux and we had the same issue with the cot. We lowered one side of it down a bit which was more comfortable for her. We feed her sitting upwards with the bottle held horizontally and then burp her after every 1oz. Hope you get it sorted. It’s rough when they’re so unsettled.