Github dislikes email “aliases” so much that they will shadow ban your otherwise normal activities for months, and once flagged, support will request not only a “valid” email domain but also that you remove the “alias” email from the account completely.
Yeah let’s say you got joe@protonmail.com, on simplelogin you can make a joe123@aleeas.com and now sign up for services using aleeas with those emails being forwarded to your protonmail
Here’s an illustration
https://simplelogin.io/images/hero.svg
https://simplelogin.io/
What was this feature called again… basically linking, right?
It’s called an email alias: https://en.wikipedia.org/wiki/Email_alias