I would also say molars... it was awful for us. It seems like you're trying to be consistent which is what most sleep coaches say to do during these blips. You're doing great mama! And motrin was our best friend until all molars popped.
I remember coming on the boards to wonder why it would take so long for him to fall asleep at BT (30-60mins) when it used to take 15! Part of that was as they get older and well into toddlerhood, it's a common thing... 30-45 mins to fall asleep. That's been what we experience except when we have no nap days.
I think I mentioned before but you want to aim for nap within 30 mins, and BT within an hour (some say 30 mins). It's up to them when they fall asleep but the more consistent you are now, the easier it'll be when teething/illness/travel/development passes.