I might throw in Buttigieg, who seems to mark points from every category and issue but each of those have another one as their champion right now. That makes Buttigieg very dangerous for the others as he can get voters from everybody who flames out, thus gaining the most in the long run when more and more candidates are folding.
I'm telling you now, dude, Buttigieg will flame out. He's a small town mayor. He's not going to become president. Buttigieg might at best usurp Harris' spot. Beto's star is already fading with progressives, so Buttigieg could surpass both him and Harris. However, if he flames out too, it'll be Biden and Bernie, until Biden flames out, at which point the establishment will pick a backup to support and put their weight behind them. If that happens, the establishment will almost certainly not pick Buttigieg. They value experience and connections, and throwing identity politics bones to whatever block of the electorate they feel they need to shore up. Buttigieg lacks experience most definitely, is forming a lot of connections with this campaign but isn't really there yet on that front either, and the LGBTQ community is not a demographic they're worried about, nor are they particularly numerous. They'd much rather pick a Latino or black candidate, and preferably a woman of color, as they view that as the biggest chance to drive turnout with identity politics. Hence why Harris is the top pick. Beto is somewhat valued because of his connections to Latinos, but he's not their first choice for a Biden backup. He does have the advantage of having midwestern white appeal, which some of the establishment want to win back Trump voters. Buttigieg has this strength too, but you should be able to see by their first pick being Biden that the most important things to the establishment are experience and connections, which would place their preferred order as Biden->Harris->Beto->Buttigieg, based on who currently looks to have any chance. But they'd much rather have several other choices before Buttigieg if they could, including Castro, Booker, Gillibrand, and Klobuchar before they'd actually pick Buttigieg on a level playing field of popular support. As for progressive grassroots, Buttigieg is on the rise with them, but not at Bernie's expense so far, and likely he'll flame out before Bernie does.