I would guess the pool of IP addressed used by Apple has been blocked from contributing since for any good faith editor, there is a vast amount of vandals taking advantage of the feature to deface articles en masse.

https://meta.wikimedia.org/wiki/Apple_iCloud_Private_Relay has some context and list potential problems that might arise (and do in your case).

https://meta.wikimedia.org/wiki/Talk:Apple_iCloud_Private_Re... is the related discussion page if you want to ask more.

Back in the old days, we maintained a list of trustworthy http proxies for which we trusted the IP of their client. The community could then block the user behind the proxy. With everything behind https nowadays, that is no more possible (the intermediate proxy can not inject any header to carry the information). So the sole thing we see is the Apple relays IPs and if those are a source of vandalism for sure the community will block them from contributing.

There is a more or less similar issue with TOR exit node for which the issue is described at https://meta.wikimedia.org/wiki/Editing_with_Tor

Given the relay is only enforced by Safari (as I understand it), you can use the IOS Wikipedia application for editing: https://apps.apple.com/app/wikipedia/id324715238 , though that will not pass through the Apple relays and leak your IP.