Professional sleep fighter

Maddi

My baby just turned 16 weeks old. She is so difficult to get to sleep. She will fight so hard until she finally crashes. She also cannot put herself to sleep. She will only nap 45 minutes at a time if she’s being held. I’ve tried using a paci, drowsy and awake , fussing it out. Nothing seems to work. Anyone have any ideas? I feel like I’m at my wits end