Bitcoin P2P transactions cannot be banned. There is no mechanism with which to detect that a Bitcoin transaction has been made, let alone detect who has made a transaction[1], since you can broadcast a transaction with a completely different IP address outside of Belarus' authority.
Exactly, but this is only applicable on stand-alone P2P platforms. I mean, decentralized P2P exchanges. I believe those are what you mean.
But when it comes to P2P means of buying and selling that's still under any centralized exchanges, they could still be traced and request account banning of their citizens, and they could still file for restrictions for their citizens not to be able to use the P2P option; it's just for the regulatory to write to the exchange. This is the reason why if one wants to remain anonymous, they should avoid the centralized exchanges and go for any P2P option out there.