i'm really stupid and delusional, so my cope for buying the skin is "it will make my account rare and expensive so if i sell it in the future i can make the money back and more"
Pretty much is the case, it's hard to actually see if an account was sold unless the account has just randomly started using a different IP for example, but that can also be excused by "I moved states" etc, extremely hard to prove otherwise outside of people being open about such activities.
Though, professional player accounts and game changers accounts are much different, I know of some game changer accounts being sold and also T2 player accounts, some banned some not banned, they care more about those accounts.
Thing is the skin system isn't like CS the value of each skin entirely depends on what value you give it. Meaning even if you manage to sell your account it would most likely be for far less money than the amount you spent. Plus the point of people buying accounts is to spend less while getting more skins so with that as a base line ur losing money from the start. You'd consider yourself lucky if you break even and someone is willing to pay the same amount of money you put in