Hugs. It's hard when they refuse to sleep so its a struggle during the day and at night. I'm thinking that he's OT so the stress hormones are preventing him from settling into a proper sleep.
Can you APOP a nap (eg. Car ride, in the stroller, etc)? I would not recommend this all the time but if he's really resisting his naps, sometimes you need to APOP a nap so he's not soooo OT at bt.
Also, how old is he now? I also think that some babies need to be physically tired to sleep well. My DS is like this (and he's 5 yrs old now!). When he was young, I would give him plenty of floor time so practice crawling, sitting, pulling up, etc so when it was nap time, he was physically ready for sleep (just not mentally ready for sleep). For naps and bt, I would PD and rest my hands on him until he relaxed. Then he usually would fall asleep.
HTH