18 week old nap time is a battle

My 18 week old, self soothes, sleeps 11hr usually at night with one early morning wake up to feed. For naps she sleeps in her crib, dark room, sound machine.. placed in awake. Naps are an absolute battle. Typically last 30 to 45 minutes ... rarely an hour. I watch for sleep cues but they are totally unreliable. She does 5 naps a day because they are so short. Does anyone have any advice for wake windows? Is this an age thing that she will mature out of?

Thanks :)