Naps - 4 months

My babe is 4 months old and I feel like we are struggling with naps a bit (in comparison to other babes at the same age, and in what I would like). She has 5-7 naps all around 20-30 mins long each. I would love it if she had fewer, but longer naps throughout the day.

I’ve tried stretching out the time between naps but I just get a fussy, overtired kiddo. I’m using the Huckleberry sleep app as well but so far it’s not really helping. We feed and change bum after nap time. She sleeps in her playpen in a quiet, semi dark room, swaddled. She often falls asleep while nursing after her nap which makes me think she is still tired too.

For the most part she goes down pretty easy at nap time. She also sleeps through the night (8pm-6am ish) the majority of nights.

Any suggestions on how I can make naps longer?