> magically appeared on the internet just a few months ago

You mean like everyone else just after they join reddit or HN? Same for blogging - there's plenty blogging and YouTubing under some cute handle rather than their given name. Plenty change names from marriage or other reasons such as abuse, witness protection or gender reassignment. More than a few have chosen to disappear, including Why the Lucky Stiff who was quite famous for a while.

All you have to do is establish a few karma points, i.e. gain a little credibility online, and vanishingly few will care what you're called or if you've always been throwaway250618.

If you go on to instigate a huge scam then people will put some effort into history and doxxing.