Kingdom over Vinland Saga for me. Vinland is great and is pretty much just as good though. Vinland Saga is far more character driven, while Kingdom focuses more on war, strategy, and politics. Vinland has a better main character and his character arc is one of the best I’ve seen from an mc, although, Kingdom’s mc is still good too. I do also think that Askellad, Thorkell, Thorfinn, Thors and Canute are better than a lot of Kingdom’s characters.
The Coalition Invasion arc is better than every Vinland Saga arc though.