Sounds like my son is a few weeks younger than your LO. We've had some similar issues...waking up standing during the night and having much more trouble going back to sleep. It'll seem like he tries for a while, then quits and wants to play.
Also, when he can't sleep, he cries hard if we leave the room - a fairy shrill, urgent cry. Sometimes has taken us 1.5 hrs to get him back to sleep! Other times, he'll go back to sleep but wake not long after. Never used to have this problem.
Just like you, people have advised that he needs more A time and less nap time...and I've been trying to extend the naps for months!..I actually still don't think he's getting enough, as he starts yawning and rubbing his face shortly thereafter. But, he's at day care for his naps, so there is a limit to how much I can do..
And, a final similarity - there are so many other factors! He's had a cold for 3+ weeks, so he always coughs when he wakes up. Maybe his throat hurts. Often it effortful for him to breathe. He's had two teeth pop through during this same time, and is currently working on 2 more. Another is right behind it. He's been constipated. I dropped his night feed...Really, I wouldn't have guessed it could be so complicated!