Curious if something like CS Surf is possible in Unity

Hello folks, I’m a beginner here in Unity 3d as well as game development. I’m enjoying the software so far, being an avid gamer of Counter-Strike and various other Source engine games I was pleased to see that I’m able to export .DXF files from Valve’s Hammer Editor and import that .DXF into Unity. Though as a personal project I’m trying to replicate Source engine’s air control & “surfing”, see this video:

I see that air control is possible with FPSWalkerEnhanced, but I can’t figure out how to control a player while “surfing” on a ramp. Being able to flick off the end of ramps to achieve a certain angle and speed is desirable, and of course as you’re surfing downward on a ramp or falling you gain speed, if you’re surfing upward on a ramp or flick off a ramp into the air you lose momentum and eventually start falling.

i actually modified a gms player controller to add surfing and to better implement strafe acceleration and momentum