The whole point of private relay is that apple does not have access to what sites you're loading. The article does a good unbiased description, but you can thin

The whole point of private relay is that apple does not have access to what sites you're loading. The article does a good unbiased description, but you can think of it as a single hop tor - enough to stop apple from knowing what you are loading, and enough to stop the egress point from knowing who is making a given request. Someone who can monitor all the entry points and exit points can probably tie the connection together, but someone in that position can probably also do that for any other vpn service (Nord, proton, etc - though those providers don't have any privacy options).