Display name vs login email
You can rename how you appear. You cannot casually change the email that owns the account.
Display name
Settings → Account. This is a label. It is not your login. It can be changed whenever you want.
Login email
This is the identity of the account. It is not self-editable in Settings. If you need it changed (typo, domain migration), contact support from that mailbox and be ready to pass security checks. We will not swap email to an address we cannot prove you control.
Confirming email
If Settings shows a verification code flow, complete it. Some domains send mail via SMTP; some show the code on screen in development. Either way, confirming email is for your recovery, not for marketing.