Update to Apple ID as I'm closing an old email account

I what to update me Apple ID as I'm closing an old email account (which is the one used for the Apple ID) I now have only 2 email addresses, gmail and iCloud.

I have:

deleted the alternant email address (iCloud)

deleted rescue email address (gmail)

I update apple ID (with gmail)

logged out and back in after verifying addresses

But when I went to add the iCloud address as the rescue address, I get an error massage that I can not use the alternant email address.

Yet I've gone back and checked there is no Alternant address.