how do I smoothly lerp/Slerp camera rotation during gravity change?

I’ve been making a sonic like game where you can go through loop de loop and using this custom gravity as help its been working well.

Except I didn’t like how the rotation of the camera was so I’ve been trying to augment but I’ve come across a snag where the pitch never properly lerps not matter what I’ve tried, so just hoping someone might possible have the answer because this issue has been driving me up the wall.