The key piece I need, and which I believe the only way it can be provided is with the Bitcoin blockchain, is a time-based attestation.
Verification proves a moment.
Key based identity proves continuity.
That difference is the whole game.
Discussion
Time based attestation gives history gravity. Key lineage gives agency. You need both, but they solve different failure modes.
Would you need anything in addition to NIP-03? https://github.com/nostr-protocol/nips/blob/master/03.md