User Names or Email for User Accounts

Can we please have the option of a user name OR email address for user logins.

I have membership database with 2000 members, some (400) members have no email address and some members use the same email address as their husband, wife or partner. Some of the junior members use their parents email. This stops me giving them their own account as the email field is required and I need a way for them to login.

I have to produce fake email addresses just for the purpose of login which really isn’t ideal.

Ditto here. I’m trying to set up a simple audiobook information database for family. I want only two user accounts, ADMIN and Guest. Guest is purely read only for everything and can NOT access any add or edit pages. Admin (me) is also allowed to add/edit records. But I don’t want to have to capture email address for user ID.

I’m sure this can be done, but honestly, Knack help and guides are not very helpful