Dropping to 1 nap??

I’m running out of hours in the day to stretch my guys wake times. Currently at 3/3.75/3.75. I have to wake him at 7, wake him from his first nap to even ATTEMPT the second nap which he usually ends up refusing or falls asleep 20 min before I have to wake him to have a decent bedtime. I know technically they don’t drop to 1 nap until 15 months or so but I don’t know what else to do. Anyone else dealing with having to have super long wake times in order for babe to sleep?

He’s sleep trained, he knows how to put himself to sleep.

Edit to add he is currently already on 2 naps.