Biden endorsed Kamala, which should end the conversation. There may be a kayfabe coronation at the DNC but I don't see any reason to expect anything but Kamala.
Don't love Buttigieg as a VP. Ticket needs someone boring from a state worth fighting for. Beshear and Shapiro are the smartest calls from what I've seen.
Kamala polls behind Trump while not even being the nominee, which makes me think her current numbers are a floor, not a ceiling. Presented as a real alternative that can coherently articulate critiques of Trump and a vision for the Dems moving forward, it's hard to see those numbers going down over the next three months.