Milk vs the fussy baby

DS is our man of mystery.
He won’t touch cow n gate (seriously he’ll take half an ounce at most)
Aptamil first gives him bad reflux
-Comfort gave him cmpa symptoms (rash/still vomiting/arching/constipation)
SMA Althera- loose green stools improvement in the rash (could just be time itself)
SMA Alfamino - violent green diarrhoea (like shot the length of my arm force) violent projectile vomiting and colicky symptoms (suddenly became a grumpy crying baby after being a very settled newbie) refusing feeds.
Aptamil lactose free (I messed up should’ve been pepti I ordered with the suspected cmpa) No rash, minimal reflux/vomiting, still a bit miffed if he’s not nursed 24/7, back to yellow constipated poop..

So on my own, by accident albeit, I’ve discovered he doesn’t have cmpa and his reflux is based on the thinner milks.

Would it be worth keeping him on the aptamil lactose free should I try something else? What’s HIPP been like for other mysterious babies?

The lactose free is hard to find locally and not sure if they’d give me pepti or lactose free on prescription either like they did with althera and alfamino. Hence the whole I don’t know if I should stick to that.