Old Apple ID cannot be updated on device

I changed my Apple ID some time ago but apparently did not get logged out of one device. I tried the solution of changing back to my old ID; however, the email no longer exists so I can’t receive the verification email.

I entered my current password and it updated partially but now just gives an error.

if I look at the name, phone numbers, email, the updated ID is there. However, when I look at the main settings page, it still shows the old - and invalid- Apple ID.

now it won’t take the password again, either. There has to be a better solution.