>We also produce an absolutely staggering amount of artifacts of all kinds, from plastic straws to giant tunnels and artificial caves.

Plastic will be gone in ~1000 years,

https://www.activesustainability.com/environment/waste-plane...

tunnels and artificial caves in a few million years at most as they are compressed by the weight of the rocks above them ("tunnel squeezing").

How long to dissolve carved stone sculptures (in sizes ranging from 1cm to 100m?)

And how long does it take to dissolve skin? Footprints? Because we have those from hundreds of millions of years ago.