I am sure over half of white Americans are related to King John.
Rich men tend to have lots of children.
The farther back you go everybody is an 8th cousin or whatever.
Is Lackland AFB related to John?
The best known group are the descendants of Henry Capet ~ there may well be batardes there but they were relatives anyway so who cared!
People like George Soros contribute at the sperm bank so we don't really know about them.
I’ve been tracing my tree for years. Once you get a royal connection, you are in luck, because the royals document legitimate births forever. You can get all the way back to BC times once you get a good one.
And in some way, everyone IS related to everyone else.
For that reason, I only bother tracing direct ancestors. It’s more interesting (to wonder what you might inherit), and I’ve found some great stuff. And learned a lot too. My favorite find is Eliot Winship and Edward Craft, who ran guns and ammo for the revolution with the Adams. And whose brother, Thomas, was in the Boston Tea Party.