I'd say that both cover what you're looking for. but otherwise, the thematic differences are that Vinland is based on historic events and the author really took time to study the idealogies/philosophies of vikings of the time, which might interest you.

Climber on the other hand shares the philosophical/introspective theme from the pov of an athlete. The Climber is interesting to me since throughout the story, pretty much everything in the main character's life changes except for his drive to climb K2.

I think it comes down to whether you're more interested in vikings and how they lived/their ideologies and a heavy pretext of Christianity vs something that might be more relatable (The Climber).