No joke, check out this project. It has exactly what you want. Extremely powerful code here even if it is hard to read. It says it's for 3.2, but works just fine on 3.5.1. Even if it doesn't run on the latest version of Godot, you should really try to make it work as you port it over to your project. It will DEFINITELY be worth it, the original author put a lot of effort into this. Great research material, it helped our project too.
When the player enters one of the gravity fields, they are attached and rotated to the floor normal collision, as far as I understand it. I have tested this on moving rigid bodies and static bodies and it works perfectly!
Just be sure to give credits to the original author.
Dynamic Gravity Kinematic Character, by Felipe Moura