Could be a build up of gas / overtiredness. Look at naps in the day and make sure his awake time between naps isn’t more than 45-60 mins at a time. Make sure lots of active burping during the day and try not feed right before sleep to help move some gas around as well. It’s a good time to look at wearing them in a wrap to help get some last sleep in during the day before bed.
Yes this lasted about 3 months for us and nothing helped.. but my baby had bad reflux
My baby did the same thing. It’s called witching hour. At least that’s what it was for mine. They are so over stimulated by the end of the day that by night time is so difficult for them.