Rotation is a really interesting subject which has true security benefits. Unfortunately manual rotation is a PITA. What works better is to have an automated system rotating the credentials, and then you fetch the credentials as-needed by authenticating with an identity and access management system.
For example, in Conjur there is a suite of rotators (https://developer.conjur.net/reference/services/rotation) for rotating things like SSH keys, database passwords, and cloud credentials. In each case, the rotator changes the credential in the backend (e.g. changes the public key in the authorized_keys file), and then stores the new credential behind an access-controlled and audited API where only you (and other authorized roles) can fetch it.
A bit off topic, but the conjur.net domain seems to be a bit broken. https://conjur.net doesn't work properly and it threw an SSL/TLS certificate error the first time I visited. Also, it appears as if your main site doesn't redirect to HTTPS. As a security company my first thought is that if you can't handle these simple things I'm not sure I'm ready to talk to you about more complex matters.
For example, in Conjur there is a suite of rotators (https://developer.conjur.net/reference/services/rotation) for rotating things like SSH keys, database passwords, and cloud credentials. In each case, the rotator changes the credential in the backend (e.g. changes the public key in the authorized_keys file), and then stores the new credential behind an access-controlled and audited API where only you (and other authorized roles) can fetch it.
Disclosure: I am CTO of Conjur.