I recently created a new gpg key just for the sake of learning the basics of public key encryption. Now, I'd like to revoke that test key so that I can go on using a more "permanent" key that is associated with my personal email account. Using the GPG Keychain application on Mac OS 10.15.*, I was able to revoke the key, and upload the revoke certificate to what they refer to as the "public key server".
However, when I attempt to search for my revoked key, I'm still able to find my public key indexed by my test email address. I've tested this on the OpenPGP Keyserver, the MIT PGP Key Server, and with the search function built into the GPG Keychain application. In the GPG Keychain, I am provided with this warning message when I try to search for the revoked key:
The following keys were found. Note that the search results come from the old sks key servers and are unverified:
My question is this, how long will it take for my revoke certificate to propagate to all the public key servers, so that my public key is no longer searchable in any way? Is it just a waiting game for the "old" key servers to synchronize with the "new" ones? Will I always be able to search out the public key by email? If so, what happens when the key reaches it's hard expiration date?