For each session. Keys are rotated frequently, so a lot of noise could be produced. The only and one address is a good strategy for anti fingerprint though, but it is not easy to achieve for WG tunnels and pure L3 routing.

Personally I don't really get their multi hop when you connect on a predefined port on an ingress server to get redirected to egress in a different region. Easy guessable for a powerful observer.

Anyway any VPN is only an encryption tool, not an anonymizer.