There is one advantage that centralised exchanges have, scammers who have stolen some Bitcoin don't come close to such platforms because they can be caught all because of KYC information, stolen bitcoin or bad bitcoins don't get sold on centralised exchange, they risk seizing or arrests, always use reputable exchanges.

Be skeptical of unrequested offers via social media where you can be given a very good offer and sometimes too good to be true offers like Discount, yes you will get the bitcoin for discount but where the bitcoin really came from becomes your problem now which can land you in big problem later.