Here's the 2026 Senate Map again.
Not the worst map for Dems compared to the 2024 map.
Decent pickup chances with Maine, North Carolina, and Alaska. With Maine, Collins could retire. In North Carolina, current NC governor Cooper might run and Tillis could be primaried. In Alaska, Peltola could run.
If Kelly is the vice presidential pick, his successor would be appointed by Hobbs till a 2026 special election. Historically appointments don't get as much of an incumbency advantage as elected incumbents. So biggest risk with Mark Kelly is it potentially puts the Senate at risk in 2026.
Likewise if Cooper is the VP, you lose a strong candidate for the NC Senate seat in 2026 that is quite winnable.
A strong argument for Tim Walz as VP is he does absolutely no harm from a strategic standpoint of other races. If you are of the opinion the VP doesn't matter, then that's a good argument.
Shapiro for that matter would also be safe from this perspective for the most part. His successor would be a Democrat. It would affect the PA legislative tie breaker though.