Reporting the player does nothing, and when you visit their player profile on Steam and see accusatory comments about cheating going back months or years, you can be confident that your report will have little-to-no impact - chalk it up as a loss and hope for more honest opponents next time.
It's not uncommon to face at least one or two players a day who are using some form of cheat (some more obvious than others). Compared to how other popular FPS titles (Valorant) handles anti-cheat, CS:GO is years behind. The cheating situation is the most prominent example of how little focus the game earns from its developers. Instead, they have taken a bare minimum approach to community outreach and maintaining a game that touts a 26 million player count each month. With the massive following that the Counter Strike franchise has and the boatloads of cash they continually bring in from digital cases/keys/skins, they most certainly have the resources to put out these types of fires immediately.
I have several thousands of hours logged in CS:GO since it was released in 2012, and Valve's lack of concern with this particular exploit seems to mimic their inattentiveness to so many other aspects of the game.