So much this. Defederation is a catastrophic issue for an average user in its current form, as the interactions fail totally silently.
Give us simple but informative warnings on reading threads, warnings when trying to post, warnings when trying to subscribe, and warnings when our subscriptions become defunct. Then the user can make informed decisions about either looking for new communities, or maybe moving to a different instance.
Your first sentence I agree with. Your second sentence I don't agree with. It's still early with the reddit exodus - things have been escalating incredibly fast and most people don't even know much about it yet, or are still processing what's happening.
Reddit was a big part of our lives for many people and it's not easy to let go. I was so deeply offended by what happened that I let go quickly even though it hurt me. But people who already used the official app? For them, it's a difficult conversation at best. But I'd say it is still early days.