For anyone curious about the issues discussed in this topic, see:

Identity and your signing key https://cirrus.earth/concepts/identity/

> Cloudflare secrets are write-only: once set, they cannot be retrieved through the dashboard or the API. This is good for security and bad for recovery. The wizard prints the key exactly once during pds init. Save it then.

Also:

Back up your signing key https://cirrus.earth/guides/back-up-signing-key/

Brilliant, so happy to learn about this!