does this game have slope surfing like CS:GO surf, and if it doesn't do you know any games that are almost exactly like CS:GO surf.

It does but it's a bit different, sort of to fit in more with the general physics and movement of the game, never aimed to be a clone of CS's surf physics. The only thing I'm aware of that might be of interest to you is

Here's an example of a surf map in rik, there's a youtube video there too: