KYC exchanges don't really exist anymore because they were abused in 2017 and thus either forced to close or comply with regulation (such as the wannacry ransomware virus, in which the criminals laundered their BTC into monero on shapeshift, which at the time had no KYC). Second, cross-chain exchanges may not be possible in a fully trustless manner.
read the whole thing. KYC only dropped for ERC 20 transactions , which uniswap already does and is not the same as a cross-chain transaction. The abiltiy to exchange erc 20 tokens is native to Ethereum.