Another typical story when someone wanted to get rich quickly and easily without much effort. For some reason, everyone thinks, after watching streamers, that they will be able to do the same (in gambling, newcomers also focus on "stars", for example, poker or lucky ones who have won the jackpot). It is impossible for everyone to become rich. It's like a zero-sum game: someone must always be a loser.

Your friend, having given up gambling, fell into the same trap with skins. This often happens. Online games have already become deeply embedded in the lives of ordinary people and the organizers of casino these games take advantage of this, creating conditions similar to casinos (causing addiction in pursuit of winning). These can be skins, as in your example, and also, another striking example is loot boxes (paid).

I easily managed to avoid it. I just never played CS:GO. I suppose that the way to "leave" a virtual casino is exactly the same as in regular gambling. That is, you just need to focus on other activities to distract your attention, which will instinctively return to gambling out of old habit. You need to find a hobby that captivates you more than gambling.