So many disclaimers about bias. I wonder how far back you have to go before the bias isn’t an issue. Not because it unbiased, but because we don’t recognize or care about the biases present.
It's always up to the reader to determine which biases they themself care about.
If you're wondering at what point "we" as a collective will stop caring about a bias or set of biases, I don't think such a time exists.
You'll never get everyone to agree on anything.
Depends on the specific issue, but race would be an interesting one. For most of recorded history people had a much different view of the “other”, more xenophobic than racist.
Was there ever such a time or place?
There is a modern trope of a certain political group that bias is a modern invention of another political group - an attempt to politicize anti-bias.
Preventing bias is fundamental to scientific research and law, for example. That same political group is strongly anti-science and anti-rule-of-law, maybe for the same reason.
I don't think there is such a time. As long as writing has existed it has privileged the viewpoints of those who could write, which was a very small percentage of the population for most of history. But if we want to know what life was like 1500 years ago, we probably want to know about what everyone's lives were like, not just the literate. That availability bias is always going to be an issue for any time period where not everyone was literate - which is still true today, albeit many fewer people.