This is too technical for most unfortunately, but the only way to guard something as valuable as your email address is to own the domain and so control the MX r

This is too technical for most unfortunately, but the only way to guard something as valuable as your email address is to own the domain and so control the MX records. I'm fortunate enough to have a grandfathered free Gmail account so I can own my domain and point it to a Gsuite account without paying. Otherwise it's worth paying up for Gsuite, Fastmail or similar.