Namely whether myskins.co is a legit site for Fortnite Accs or whether they are scamming?
In my opinion the MySkins system is kind of a scam, yes. The description advertises that it is a "very valuable" account, but the content of this does not correspond to the description.
In general, the (selling) buying of an account is prohibited by the terms and conditions that you accepted when you created your account. If this is discovered, all accounts will be blocked by you.
That's why I always advise against buying accounts - no matter where.
Nice day!