it's a solid story, the main character has a nice background, and the story has good world building because the author uses the fact that his main character is a historian and develops around it.
it does have some issues though, the first that comes to mind is the unrealistic politics, another is how the main character changes his mindset quickly, also the portrayals of can canon characters, and the bashing tone of the story, it's not there outright but you can tell.
Another thing is that there is no solid reason given on why the mc does what he does, why he goes to such lengths. he also has a sort of god complex where he thinks he knows the characters, like in the chapter he's thinking of making Ned a wolf he has an internal monologue, and goes on a rant about how Ned is a foolish man who ruined house stark, and how Jon's line is better than Brandon's line, and it suddenly spirals into how he knows he can manipulate Bobby B.
the final thing I have to say is about Torrhen stark, it seems that the protagonist truly doesn't understand why he knelt instead of fighting, the north had no more shifters at the time, and even if they did I doubt it would make that big of a difference, the fact is that as honourable as fighting sounds, they were up against dragons and Torrhen is a king so he has to protect his citizens, fighting against flying giant fire breathing lizards isnt exactly doing that, and also It was the correct thing to make his big brothers son his heir since it was rightfully his from the beginning.
this is all I have to say, apart from the highlighted problems it's an okay story, great world building. I'm looking forward to more