And, as a personal thought: It would not really matter if the dating methodologys used, later came up with a major correction, reducing the date from 300,000 years BP to say 10,000 years BP. It would still indicate that the Genesis account is only what it is, an origin myth, trying to (but not succeeding) in explaining how humans came to exist on this earth.
And, the dating is only one feature, the other more important feature is the differences in the skull, similar to modern humans, but not identical. The Genesis account can give no reason as to why we can find similar human remains in different locations around the planet,
What do christians imagine that the YHWH/JESUS designers were doing? Experimenting with different creative designs, until they got it right (in their own image-grin!!)? If YHWH (at least) is perfect as imagined in the Jewish sacred texts that christians now call the Bible, why would he need to experiment. Surely. he would get it right the first time?
And, its not just humans, there are animal remains from the past, similar to modern Australian fauna, but much larger, like this giant platypus:
over one metre long. Was that a failed creation also?
http://newsroom.unsw.edu.au/news/science/giant-extinct-toothed-platypus-discovered
There are others too, browse this Australian Museum site to examine them:
https://australianmuseum.net.au/australias-extinct-animals
And going back a bit further you come to the dinosaur type life forms,
The Genesis account makes no effort to explain these extinct life forms. Why? because the author of Genesis could no nothing about them - therefore neither YHWH or JESUS (if they exist) could be the authors of the Genesis account.