Even if you restricted it purely to 2022 Minnesota elections, Walz did well, but not massively so for an incumbent. And Scott Jensen was a pretty awful Republican opponent. The best arguments for Walz are he does no harm both for the base and for future elections.
Arguments that he can help electorally are mostly based on vibes rather than his actual electoral performance. The other candidates have stronger arguments in that regard- both Kelly and Shapiro overperformed in their states. And Minnesota ain't really a swing state like Arizona or Pennsylvania.
That being said, most of the candidates aren't well-known to the national electorate, so there's some uncertainty to how well it will translate outside their states. But then again most of the effect of the vice presidential candidate is isolated to their home state anyways.