Regression just in time for RTW

My 3.5 month old has recently routinely started waking up 3 times per night to FULLY feed… we’re on formula (transitioned from EBF early because I refused to pump at work again). Last 3 nights this has roughly been our routine:
- 6:30 pm -last feed before bed 5.5 oz
- 7:10 pm - Asleep in crib
- 11:00 pm - 4oz feed
- 2:00 am - 4oz feed
- 5:30 am - 4oz feed
- 7:45 am - awake and off to daycare

Before this last week (his first week at daycare mind you) he was waking up 1 to 2 times at night to feed within a 12 hour period…

I want to sleep train ASAP however, I’m really scared I’m creating a bad habit in getting majority of calories in at night… he just seems legitimately hungry! He downs his bottles!

During the day, he is a super finicky eater… usually does 2 oz just fine then it’s a fight to get him to take more… daycare hardly has the time to deal with that and even in days when he is home with me I struggle to get in the extra oz per feed… I know daytime calories are an issue but I can only lead a horse to water…

Any tips on this? Should I lessen the amounts in the night feed bottles? Slowly try and stretch the feeds apart? HELP!