The slopes in my game are all slippery, they (and the player) all have no physics materials and i copied the movement system from this youtube video and modified it to work with the new input system. Thanks for reading.
Add material with friction
I tried with both dynamic and static friction, they all didnt work
My only advice without going through that entire tutorial would be to not use the new input system go back to the original and follow the tutorial exactly as its shown without any changes, also make sure your rigidbody settings are exactly like his are in the tutorial.