5 month old fighting sleep

My 5 month old is fighting sleep soooo bad and it’s making me insane. She will literally stay awake for 4+ hours at a time which I know is too long for a baby her age and it then makes her overtired, but I literally CANNOT get her to fall asleep before that point. I’ve tried rocking, nursing, walking around, carrier, just putting her down, everything I can think of and she won’t go to sleep until she just can’t stay awake any longer. She also only naps for a maximum of 30 minutes when she does finally fall asleep. Anyone have any tips to help with this? My first was not like this at all so I am at a loss.