Need Help Trying to Keep my 5-6 Month old asleep at night

So Background, my little one is 5 months old, was born 36 weeks old 5Lbs, Now is pushing 20 Lbs. Diagnosed with IUGR while in the womb. Sleep has kind of always been bad, Primarily contact napped until about 2-3 weeks ago, able to put him in the crib while hes a sleep during naps for about 30-50 minutes, if he's fussy I will contact nap him to make sure he gets adequate sleep. Dealt with reflux and colic symptoms and for a while haven't really seen any symptoms. During the night he would always sleep 2-3 hours and wake up to feed or needing comfort. Pediatrician has given Omeprazole, doesn't really seem to help with anything, its been about 2 months since he's been on it.

We have a constant bedtime routine, little one randomly wakes up sometimes 5-6 am usually asleep and in bed around 6-7pm latest 7:30pm.

Recently in the past two weeks, our little one at night has been waking up almost every hour or two, crying, scratching his face and fussing around. We originally thought maybe cradle cap is itchy or his face is itchy, moisturise, did everything but still does it, we now think its his way of attempting to soothes himself but it definitely wakes him up more than soothes him. Now were both not really sleeping, its taking a tools on both of us, we both work, wife refuses to stop working for her own personal and wants to keep autonomy etc. We have tried everything, different swaddles, A/C all night, Fans, different types of sleeping. Right now the only thing that consoles him when he wakes up is rocking or contact sleeping with me or my spouse. What do you guys suggest, We really want to get away from the contact sleeping.