Hi there, it's certainly an intense time, isn't it? (((Hugs))) I'm with choc here, sounds like OT, as you yourself thought. Most LOs her age would actually be getting three longish (if lucky!) naps plus an evening CN - which when my DD was this age, was taken in a sling in a quiet corner of our car park (no garden or we'd have done it there!) whilst kicking a ball around with my (then 4yo) DS
That evening CN can really help them get to BT without getting OT, and you'd try to keep the A times as short as possible before and after. That reminds me - do you try to reduce the A time after a short nap? That can also help stop OT accumulating over the day. How does that sound?