You can use an Escrow Service to avoid scammer went doing a transaction. If your transaction on Telegram/Discord without Escrow, just same what are you doing it here. Rules went transaction only "Don't trust anybody", maybe you can use an exchange service for OTC Trade example Bit-Z exchange have a service for OTC trade.
Escrow is the best solutions for everyone who want to make transactions in cryptocurrencies,,
i think its better to make a transactions here in this forum, because a lot of trusted escrow service in this forum,
i hope the OP will think about that,
for the OP just go to marketplace sections in this forum if you want to buy or sell any cryptocurrencies and always remember to use a trusted escrow service