Unable to download Apps after changing my Apple Account primary email ID
I originally set up my apple ID with my work email. Quite some time ago, I changed the primary email address to a personal email as I was retiring. Sometime in the last couple of weeks, my phone reverted back to the old work email. I've tried to correct it under Sign-In and Security, but the old email address isn't showing up there. However, if I try to make a purchase in the app store the old email is defaulting and asking for a password. I have no idea what that password was. At this point I can't download any apps or make any in-app purchases.
[Re-Titled by Moderator]
iPhone 14, iOS 18