One way #nostr clients can improve #privacy today would be to support the use of proxies (http or socks, possibly with authentication). Rather than reveal the client’s IP address to the relay, the proxy’s IP is all the relay will see.
I thought this could be solved today by using custom relays that are just proxies; for instance wss://my.relay.proxy/nos.lol could just be a #proxy for wss://nos.lol and all nos.lol would see is the IP address of my.relay.proxy but that interferes with #nip65 so it’s better for the client to directly support proxies.