How the F do I drop the 4th nap?!

Is there a step-by-step guide or something?

4 months LO keeps fighting naps but is giving all cues at 1:30-1:40h mark, then he fights. I extended the WW to 2h, which worked well for 2 days and then he fights again.

Today he decided to fight his second nap for 30 minutes, which pushed the last nap to start at 6:30. I always cap the last nap at 30 mins, so when he wakes up at 7pm he is furious and fussy throughout the entire wake window, which tells me he really doesn’t want to be awake at this time.

He exclusively contact naps. Usually, the first or third nap is the longest one - 1.5 h, which is extended with minimal rocking/shushing, the rest are 30-45 min craps.

Total daytime sleep 3-3.5 h. Total awake time 9.5-10h. Awake for the day at 6:50-7, if the bedtime is later, he sleeps until 7:30. The ideal bedtime would be 8pm but lately it’s been 8:30-9pm because of his fighting and scheduling issues I can’t crack.

Wake windows for the previous two days were 2/2/2/2/2

Today they were all over the place: 1:50/2:20/2:15/2/1:45

Please help🫠