Well, Source was the last Counter Strike game that allowed people to use custom skins. CS2 enforces sv_pure when playing on official servers, so you can't make up your own skin and use it. It sucks.
Using custom skins on official servers by modifying game files has always been forbidden since CS:GO. CS2 doesn't make it worse. Join a community server if you want to use your own skin you made up.
At one time[1] Valve even tried to ban community servers that offer custom models/skins. Though they doesn't seem to enforce it anymore.
At one time[1] Valve even tried to ban community servers that offer custom models/skins. Though they doesn't seem to enforce it anymore.
[1]: https://blog.counter-strike.net/index.php/server_guidelines/