I hear you but remember before the Internet there was the printing press and publishers and those running them are always careful about what gets out and what doesn't.

So pretty much anything available in book form has to be scrutinised heavily because there will be bias in what is trying to be highlighted. So it gets grim and people on the Internet are just as trustworthy (Or the opposite) as anything you can actually touch with your own hands.

Archelogy, anthropology and economics seem to be good indicators across the different eras and don't contain opinion often because evidence and speculation upon it is all there is. Whatever the opinion of Jewish people is at any given moment in history you can state that they are resilient people and highly adaptive and yet insular wherever they go.

The archives of Alexandria being burned down are a good starting point if the Romans and their opinion of everything which came before them as a civilisation is your interest. Istanbul and the Silk Road also make for reasonable areas which contain more about what was established and fully operating before being snipped from history.

Pick a starting point and then extrapolate from there because it is a vast tapestry and there are no concrete answers. If biblical studies are your thing then Sumerian history and how that expanded into Europe and India might give you some background as to how important Judaism has been to what we consider to be culture.

But it's a lot and the Romans, while incredible important, only left us their history to take as THE history to go from.