The only solution I’m thinking is convoluted but I’ll mention it anyway.

Before being censored, a person publishes a btc layer 1 public key via Nostr, and then Nostr clients (or separate tools) could scan the btc chain for any inscriptions from that public key as kind of a “ground truth” announcement from that person. So everyone/client goes to the same place (btc layer 1) to check for messages. Also could be used to make an announcement in the case that your nostr key becomes comprised too.