It will definitely be somebody relatively safe. She's definitely not going to pick a member of the Squad, Warren, or Bernie. Buttigieg and Newsom are the least safe names I've seen mentioned and they are probably well behind the others: Cooper, Kelly, Beshear, Shapiro, Walz, Whitmer. All of them are moderates.
VPs generally don't help much and tend to make things worse. I think he's clearly already the second worst pick in my lifetime (behind Palin). He's simply said way too much extreme stuff in the past (with the worst being about childless women so far). Pence was arguably the most helpful as he helped excused Trump's lack of "family values" to evangelicals back in 2016.
https://www.yahoo.com/news/trump-shortest-term-official-predicts-141704355.html Trump’s Shortest-Term Official Predicts When J.D. Vance Is Out
He did grow up working poor with a very dysfunctional family. He got a very generous financial aid package to attend Yale. Actually I'd call it a DEI admission. He did however earn the nod with good grades and high academic achievement, but being poor white trash did help. I give him credit for making the most of the opportunities presented to him. He isn't a bad guy, just brings nothing really advantageous to the ticket and as things are turning out Trump might need more than a yes man sidekick to put him over the top.