"History is just one damn thing after another"
I was a History major in college. Basically that means that you read a ton, write a ton, and try to understand why certain events happened - and - what those events did to cause things to happen afterward.
Much of what we know to be true is someone else's version of what happened. They say "it's not what you don't know that gets you into trouble, it's that what you know to be certain, that just ain't so."
Events have different interpretations when viewed from different perspectives. Our job is to know the facts and to understand the different perspectives of those facts. Emphasis on understanding; meaning emphasis on how we think through information we're presented - and what that may mean to future events.
Learning how to think through the information we're presented is the important (and hard) part. Biases are hard to shake.
The only way I know to do this is to deliberately look through different lenses or perspectives to get the broadest picture possible. This means leaning into opposing perspectives. If we understand different perspectives we get closer to seeing the full picture of the truth. This takes practice. It doesn't come intuitively to most of us. It's always easier to start with an assumption, then render judgement, with bias.