nostr:npub1exv22uulqnmlluszc4yk92jhs2e5ajcs6mu3t00a6avzjcalj9csm7d828 servers don't see a lot of metadata, no. Maybe IP addresses.
Discussion
IP + channel + date and time of messages + payload size. And if you use the same server for all your contacts (which is what everybody does) then they can see the group of channels you talk to. If both sides use the same server (which is common) the server can map IP to IP, geolocate the pair. Track IP over time and you can isolate work/home locations and from there you can know who the person is, with good probability of sucess.
I think we've discussed this before, I think IP protection is the job of another layer.
From what I remember what you have in mind you want a set of nostr relays to perform a sort of mini-Tor routing. Dunno about that how that works and whether that's not the wrong layer.
Sure, nostr could also use extra layers. But COULD doesn't matter. It's either there by default, for everybody, or it's not solved.
If you want nostr or SimpleX to solve the IP masking problem then you don't understand tech stacks. We use different solutions for different layers in our tech landscape, instead of bundling layers with apps.