Thank you for your feedback :)
I used only box colliders at first but I didn't get the slippery feel i was going for which was why I decided to use circles for the bottom part. But tbh it was a quick fix and could probably be better achieved with only a box collider with some more work.
I have coyote time added, the problem is that the rigidbody is slightly moving when it's on top of another character, making the velocity change in both directions.y quite frequently. I'm aware of where the problem occurs in my code but decided not to fix it since this was very much a quick prototype and I set my deadline for this jam on Sunday.