I want to uncouple my AOL email account from my iCloud email. Now, all AOL email appears on my iCloud email. I want to keep my AOL email separate. It was a mistake to include AOL email on iCloud. How do I undo this?

If you want to change email address then you can change it on Apple's website. But keep in mind >> remove your emails from your every device before changing your email address. Otherwise you might lose you previous email and will be unable to recover. Also your devices might be locked permanently because of changing email address while being signed in.

There are two email addresses.

Means your @AOL email is seperate and @icloud email is seperate. Actually your @AOL is icloud email if you are logging in to Apple services >> like on icloud or Apple website.

Please check if you are mis understanding these emails. I think they can't be synced with eachother.