Generate new ones for new use cases. On the extension it’s just a single click, to on-boarding. I expect nostr users will have 10 keys for 10 different unique use cases in the future.

same here. nostr key management will likely become a bigger topic in the months to come not your keys, not your identity. ...I am pretty sure there will be ways to backup/ migrate keys in the future though. has to be possible, I can feel it.