I've submitted a patch to the event deletion NIP (09.md), adding the possibility to burn or retire an npub, rather than merely emptying it of events through deletion.
You can see the proposal and comment on it by opening the note below or by clicking https://gitworkshop.dev/repo/nips/proposal/23791a60b65c898b2eaa500323ef918e0c9d61b6a6dc16d7da42a3cc935075d7