Unable to update apps linked to an old Email address
Several of my apps are under an old email address which I no longer use. Can't update.
[Re-Titled by Moderator]
MacBook Pro 13″, macOS 13.6
It sounds like in the past you wanted to change the email address used for your Apple ID and probably created a new account instead of doing it the correct way and updated the address on the old account. In that case if you are now using a new account you will have to delete the apps (and all their data) and download them with the new account.
A more complicated method would be to log into the old account and set up Family Sharing with yourself under the new account Set up Family Sharing - Apple Support