feeding to sleep

Recently my baby (4 months) has been having issues with naps and she hates rocking, shushing or patting to sleep. Laying her down in her crib in a calm and dark environment doesn’t make any difference - she just wants to fall asleep nursing and stay on the boob for 20-50 minutes. I’ve started wondering if it’s because I haven’t previously discouraged nursing to sleep and now it’s her only preferred method. I don’t even know if nursing to sleep is “bad” as it seems quite natural but I’ve previously come across opinions saying that it can be an obstacle in long-term sleep habits?

She CAN self soothe to an extent because when she wakes up at night she always falls asleep on her own.

I’m looking for any opinions or just your experiences. Im happy to let her soothe that way but the constant contact naps take away a lot of my day!