How accurate is Macbeth?

The tragic play of Macbeth is arguably one of Shakespeare's best works in the eyes of critics. It's a story based on the events of past history about a man driven insane by his own ambition, which has parallels to real life events. However, even knowing this, that doesn't mean that it's a perfect retelling of history itself. In fact, Shakespeare got a whole lot of facts wrong! First of all, Macbeth did have a legitimate claim to the Scottish throne. He was the son of a grandson of King Malcolm II, and was the cousin of Duncan. In Macbeth, Duncan is thought to be a strong ruler, but in real life, he only ruled for six years and his forces were defeated often, so he wasn't seen as being very strong. Macbeth did kill Duncan, but not in the way of the play. Instead, he defeated him in battle. Macbeth then ruled for seventeen years, only finally being killed in a battle by Malcolm III. As for Lady Macbeth, she was real, but there was little known about her. We do know that her name was Gruoch, though, so that's a thing. Finally, Banquo and Macduff were likely fictional and only added into the play to make it more interesting of a plot. So, Shakespeare - what gives? Well, I guess you can excuse him. It's more interesting in the play, honestly!