My mother has an iPad and lost/forgot her Apple ID

I apologize for the lengthy question.

My 85 year old mother has an Ipad and lost/forgot her Apple ID. Being 85 years old, her memory is getting bad and she can't remeber any of her previous passwords. She also does NOT have a smartphone/cell phone so it can't be reset that way via MFA. She even took her Ipad to an Apple store because the email previously assigned wasn't working. She used to have a gmail account, but just for the purposes of getting email working on her Ipad, the Apple person had to set her up with an Icloud email account. We have tried all the standard ways to recover it, but they haven't worked. Any suggestions? I thought about scheduling time with another Apple store person, but don't want to waste me time if they can't help.

Also, Can NEW Apple Id be setup with a new email address as a possible resolution?

Your help is greatly appreciated.

[Re-Titled by Moderator]