Hi, my 6 month old is exactly the same. He is quite easy going but has a lot of energy and is always very alert and wanting to be somewhere else.... do you know what I mean. If we're sitting down he wants to be on his mat,; on his mat he wants to wriggle across the floor etc - not the type of baby to be calm and chill.
He will go for 2 - 2.5 hours max and it's really hard to find a balance between giving him enough stimulation so that he naps well but not too much so that he flips out and cant fall asleep. I watch his cues but sometimes there's nothing then all of a sudden, eye rubbing etc.
A couple of weeks ago, even 2 hours was way too much and all my friends babies would do 3 or so but then all of a sudden he extended so definitely watch your lo's cues and it will come.
xxx