It wraps up the plot points, but as others have said it was ridiculously rushed. There was no time nor actions to really give motivations to characters for their actions. This was not a movie written as a movie to wrap up the series. This was a movie written as a 10 episode season where they removed all buildup and fluff granting character motivations and just quickly moved through each plot point. I'd rather have had a final series than this movie. All the plot points were good and made sense, but how they got there was so confusing
SPOILERS **** EXAMPLES
Ingilmunder had Aehelstans ear, there wasn't really any reasoning, but Aethelstan just 100% trusted him and acted without any reasons behind it against longtime friends and allies
Aldhelm dying. Aethelstan just takes the word of some random chick he's never seen before and kills one of his most long served and trusted advisors with barely any hesitation.
Aethelstan being gay was in the books. However it has NEVER been hinted at leading up to this movie. And now its part of the plot to why he's acting out because he wants to correct the sin. Shoehorned in
Ingilmunder escaping prison with the christian ladies help. No buildup, was like 2 5-10 second scenes and then it just happened. The motivation was he was Christian, that's it. No manipulation
The whole meeting of the kings who united against Aethelstan probably did the best of explaining motivations and reasons to do as such, but this would have been a 3-4 episode slow burn of events that would have led to that in a series
Uhtred losing his sword then getting it back seemed to have absolutely no significance. He just lost it in a scrum (has he EVER lost a scrum to this point?). Then sees it later and demands it back basically. No explanation of what it meant (we all know from the show, but this is a silo'd movie), or even what it meant to get it back
At the end Uhtred gives over his kingdoms to Aethelstan to be the king of a united England, and Aethelstan just immediately claims all of England is united then despite the fight scene ending with 6 ravaged kingdom armies and angry kings with zero resolving what happened there.