Unless it was burned, melted, decomposed or crushed to dust, it's all out there or in a landfill somewhere.

I do find it difficult to believe that we would not leave enough fossil and mineral evidence for future paleontologists to find. I get that the surface will churn, but layers of rock routinely become exposed, revealing the geological history of the area. No tea cup shards, no impressions of rusted cars in the mud, no concentration of metal in strangely rectilinear formations that suggests skyscrapers?

There would still be many signs. Dug up mines, metal alloys that don't exist in nature along with refined metals in quantities they don't exist, animal and plant species we bred along with all the ones we made extinct.

Very few things would in fact remain, you’re correct. But we’ve also created radioactive elements with half lives of many millions of years.

While there would probably very little direct evidence of humans after millions of years, there would probably be at least some anomalous evidence someone could find.