How to make a Character Controller that Slides Down Slopes

How do I go about creating a character controller that can slide down slope in the same way as the modern Far Cry games?

I’ve spent over a month trying and would really appreciate if I could finally get an answer to this, thanks.

Tried once, you need to know the inclination of the floor, one way is to raycast down and get the hit normal. Then a lot of math and physics to get the sliding. Or just get the angle and slide acording to it.