Well as of right now the Democrats have a solid lock on state wide elections. If they’re going to do it, now is the time. A 2 year incumbent that doesn’t leave the party is highly likely to get reelected.
Shapiro’s also got some baggage, his Israel position for example. Kelly however will be vulnerable to a swift boat attack. However as VP that will have less impact than as a candidate. Whereas the Israel issue will cause some of the left to stay home.
It’s all really complicated, I’m sure they’re putting a lot of thought into it.