Hi there, I think he's prob ut for his second nap, hence all the difficulty you're having (and the resulting short nap).
Maybe try putting him down 30 mins later and see if that helps. If you find that's still no good, maybe try capping first nap at 10 mins.
Also, just wanted to check what you mean by "some form of CC"? As you may know, bw doesn't believe in CC because it breaks the bond of trust between LO and parent. However, if you mean you're doing WIWO (see FAQ board if you're not sure what I mean) then that would be different as you'd be listening to your LO and going in when you hear an "I need you" cry. Lots of LOs settle better without a parent's presence and so of course you don't have to stay with them if their just making settling cries rather than I need you cries. Another option rather than WI is to try shhing or saying a sleepy phrase from your lo's door if/when they get upset.
However, hopefully if you try putting him down a bit later you'll get less resistance.
WDYT?