P2P platforms allows trade between two parties without the exchange interference but that doesn't qualify them as decentralized when their servers are centralized.
Exactly. LocalBitcoins is peer to peer but it isn't decentralized at all. HodlHodl is peer to peer and semi-decentralized, but still has a centralized website which all functions take place on. Bisq is peer to peer and the most decentralized exchange we have at the moment, as each user runs the software on their own computer, but still has a few centralized components (the arbitrators for conflict resolution).
Not requiring KYC, while necessary to be classed as a decentralized exchange, is not sufficient on its own to make an exchange decentralized by any means.