you might be at the very start of the 1-0, when the nap starts to affect night sleep.
For us, when naps started to reduce night length, L could get in an OT-UT loop. She would be OT overall but still a nap made her UT at BT from the nap.
what helped us was capping the nap back gradually to keep nights as long as possible, BT at a constant time, and minimise BT resistance.
you said nights were longer with a 1hr nap, maybe stick with a 1hr nap for a while and see how that goes?
However, others prefer to keep a long(er) nap and put up with short(er) nights.
It will depend on what suits you and your LO best (some LOs really don't like their nap to be capped
)
Some ppl find that they can just get away (for a while) with moving the nap later, keeping it the same length, but the long morning A time means that they are still tired at BT.
So, lots of options!
Have you read this?
The 1-0 transition...Advice and Tips to help you through.