How to get past Google blocking gmail smtp access?
I have painstakingly found the final answer to this:

Google will ALWAYS block SMTP logins from anywhere, even their own gmail app, unless you turn on the  'allow access from less secure' setting in your google account's security (https://myaccount.google.com/security)

In order to use a gmail account as a non-native gmail account without the allow-less-secure setting is to use an app that actually uses the google pass-through login.

The gmail app does not use the google pass-through login, because, why would it , it's already a google app.

The only way to use a gmail account as a non-google account inside of gmail is to use SMTP, which will require the less secure setting turned on.