How to change Apple ID alias to match new Apple ID

Changed my Apple ID to a new email address. However, the @icloud and @me addresses remain the same as my old email. I know I can create aliases but these aliases cannot be removed because they say they’re an alias of my Apple ID address (old one at that.)

So to simplify it this is what it looks like:

old Apple ID : oldemail@gmail.com

new Apple ID: newemail@gmail.com

and currently the @icloud.com and @me.com addresses are:

oldemail@icloud.com and oldemail@me.com

How do I delete or change the oldmail@icloud.com / oldemail@me.com to newemail@icloud.com / newemail@me.com?

I’ve already created additional aliases, but would like to remove the old ones that were created when I initially created my Apple ID with my old email.

Thanks in advance!