Lots of hugs! Your DS sounds sooo much like mine at that age, so I wonder if what worked for us might work for you? I'd always thought that 30-35min naps were OT, but it seems not necessarily. Is it possible that he might be ready for an increase in A time? This really worked for us. I would try and keep him up a little bit longer before the first nap, even if he'd had an unsettled night and EW. Usually this would backfire in that he'd wake OT after 30mins, but at least I knew for sure that this was OT rather than UT, and he'd be easier to resettle because he was actually tired. Previously, I think I'd spent way too long trying to resettle him when actually he wasn't tired, as the A time needed stretching. I do think that your LO sounds like he's not tired enough to go back to sleep after his short naps, and if he's not getting enough A time during the day that can certainly affect the nights. The other reason nights might be affected is if the first A time is too short, and then he does a short nap, then he could be getting OT throughout the day.
So, maybe try stretching the first A time, keep him up longer, but then if he doesn't resettle after a short first nap, then try to keep subsequent A times short, and you may find he ends up with an early bedtime but that's ok and may help. Longer 1st A times and earlier bedtimes certainly helped our DS's short naps and NW/EWs!
As for resettling, our 'shh-pat' changed over time to be just a hand on his chest and as little noise or interaction as possible, as this seemed to wake him up more. But each LO is different so yours may still like the shh-ing, I don't know. If it's any consolation, our DS's naps are only just now getting better!
One more thought - when he goes to sleep, are you in the room with him, or do you leave the room with him still awake? We started leaving the room when he was still awake at around 5mo I think, and that may have helped him to resettle himself when he wakes - since he's used to going to sleep without anyone else in the room. Just something to think about, yours may not be ready for this yet, you know best!