Ah, you’re right, Connect is just for Android. Though I do remember hearing of an iOS Lemmy app that could block instances at a user level, but I’m sorry to say I don’t remember the name.
That being said, I fully agree with you on relying on instance admins to defederate / block instances. I prefer to have the agency to choose for myself what gets blocked / not blocked. Though I can’t complain about my instance’s decisions so far, thankfully.