We are going through something similar! it is so tough.
For us, sleep was clockwork until around 2 years. Now we go through cycles of good and bad.
Right now, at 34 months, Soren is dragging out bed time and making tons of requests and even sometimes waking in the early hours (between 3-5) and making more requests (a band-aid for an owie, lotion for 'itchy' skin...wants to talk to Daddy on the phone when he's away at work). Sometimes she goes back down, sometimes she is up for HOURS.
We've capped her nap at 1.5 hours since her usual 2-2.5 was making her bedtime super late. However, we've had only a little success at implementing an earlier bedtime and she's usually awake until the later time anyway and then wants to sleep in.
Naps are still good but nights have really gone to pot with the NW. I also think developmental stuff is going on and it's really throwing everyone for a loop.
I have noticed, too, that at her age, any shift in routine (a trip, a new stimulating outing) only makes everything worse. She used to adapt but not anymore. It seems like she gets super stressed really easily and, when she's overstimulated, only gets more hyper and gets less sleep.
She will be going to school in a little more than a week and I'm really worried about her rest! She'll need to get up a full hour and a half earlier than she does now and go with a longer A in the morning. I am freaked out about it and am scrambling to make an earlier bed time work!
You're not alone! I think this is just all so exacerbated by the willful toddler stage and we'll be doing much better when they move out of toddlerhood. LOL.
I also want to hear about how your progress is! Rooting for you.