I mean, the existence of lead doesn’t necessarily prove the age of the earth so much as that those elements have existed for that long.

HOWEVER – you’re basically guaranteed to find lead in uranium deposits found around the earth, and the ratio of lead/uranium is how we calculated the 4.6 billion years.

Uranium is formed in Neutron stars or Supernova, so at the very least - the uranium found on earth itself is 4.6 billion years old. Whether “Earth” was “Earth” back then, who knows. This could be pre-moon? Could be before the earth even cooled down to have a solid outer layer? So the estimate is bound to be off by a little…

Just not by 4.5 billion years.

I’m pretty sure just soap has been around for more than 4k years.