Animal abuse. I could not get through Black Beauty and I do not like that cruelty towards cats shows up in a lot of critically acclaimed books.

I think you are making two important points here:

1. It is a good book. He is a great writer and the book being based in reality or not doesn't really take away from that. If anything I would see him as more of a creative storyteller if he simply made most of it up.
2. When we tell stories about ourself they become just that. Stories with us as the unreliable narrator. Sometimes we remember things wrong, sometimes we draw the wrong conclusions when we lack information and sometimes we embellish or lie. But we always experience and look back on things with our own bias, If I have been told that my uncle was crazy then that is going to color my memories of him. And there is not going to be some sort of all knowing and neutral third party to tell us or others what is 'really' true.

My experience is that as soon as a thriller is the least bit gory the female characters will be just fucking terrible. Even when the author or one of the authors (I'm looking at you "Lars Kepler" aka Alexander and Alexandra Ahndoril) is a woman.

You see that rune that looks kind of like a bow? That was not used by vikings. Same for the one that looks a bit like a capital M. They ARE runes, they just were not used in Scandinavia at the time vikings were active. Also that picture from 1928 (I think the year was) where some people are sitting on the stone? The runes look weird and I’d be surprised if the picture hasn’t been retouched.

I haven’t read those but when reading a historical novel it’s always worth to keep in mind that places change. What is today a fashionable neighbourhood can very well have been an absolute dump no one would set a foot in voluntarily just a few centuries ago.