I kinda half accepted this is just how DS2 (23 months) is. He's always way too alerted. No matter how I twist the routine (in an effort to make it right), if it happened to allow him sleep earlier/woke up later, he somehow always lose the hours of gained sleep elsewhere by waking up earlier or falling asleep late.
When he was younger , it was even worse, any tiny noise could wake him up in the middle of a nap.
There was about 5-6 weeks or so in laTe March, he was able to sleep 13 hours in total for a day. I thought that was a good pattern. But it didn't last. One day he went to nap later than usual, all got messed up.
In the term break, he slept less than DS1 (8yo), who got a solid 12 hours every night. And DS1 had always gotten 14 hours sleep when he was little.
I guess I will just have to accept this is the way he is naturally???