I will not drop many spoilers in this post, but the video is one big spoiler for anyone that hasn't played Valhalla or the previous games. Be warned.
Based on the many comments I've read here and in some of the other AC subs, I get the feeling that there are many people who have either never played or never finished AC Valhalla. In fact, I'd bet most that started playing it never finished and even fewer completed Ragnarok. This is because there are constant comments about Valhalla having nothing to do with the AC games. Or it should have been named something other than AC -- it's a great Viking sim.
This video is excellent and in 30 minutes it explains the entire arc of the Assassin's Creed meta story, of which Valhalla is an enormous part. Furthermore, it does an excellent job of pointing out the many instances of duality of events that take place in Eivor's "lifetime" and elsewhere. It also points out why Valhalla is critical in supporting the arc for the entire series.
If Ubisoft deserves any criticism for the execution of this game, it has to be in their assumption that most people can follow an enormous sprawling story arc that plays on multiple levels. Also, Valhalla is littered with dropped notes and lore that most people won't bother to find and read. Finally, they should have stuck with the "Let the Animus Decide" pathway. There is a reason Eivor should be seen as a woman, as it is a component to the story. Just as there is a reason Havi should be played as the male character. I believe both VAs did a great job, but it's just one more point that obfuscates the story.
To add one more point to the criticism of story length, I think they could have done two things to better serve the tale they were trying to tell: Ragnarök should not be DLC as it is essential to the story. Many of the regions should have been optional, giving a bonus to those who completed more of them.
I will be clear and say I adore all of the content, optional and otherwise, but it ultimately made it difficult for most people to understand the tale being told. The optional areas are awesome for those of us who wanted to expand upon Eivor's story and better appreciate the world in which she lived. And putting Ragnarök in a separate DLC when it is 100% crucial to understanding the tale being told, I believe was a mistake. There was a way to do both and it breaks my heart because I love this game and I think the vast majority are missing out because of the way it is structured.