Change RSA encryption key?

How would one go about changing the RSA encryption key of a repository? Ideally, this would not require having to re-upload the entire backup. I think copy may be what I’m looking for but having never used it before, I’m not sure how I’d go about it.

The RSA encryption key can’t be changed. Yes, you need to create a new compatible storage and then run a copy command. See this guide for details: Back up to multiple storages