I don't think many Democrats are supporting Haley for any purpose other than to have her stay in the race and rattle Trump.It’s kind of an odd strategy. Democrats believe Biden can truly beat Trump, but it seems that those concerned about his age as the deciding factor would rather give voters Nikki than a Democrat runner up candidate. Harris and Democrats’ meritocracy is probably the biggest roadblock to this. Whole lotta "It’s their turn!" driving the Democrats and not enough nutters to derail that plan.
Part of me believes Newsom is a shadow candidate who won’t make it known until Biden’s age related behavior becomes an issue to even the biggest holdouts.
As for an alternative to Biden, I suspect a healthy percentage of Democrats would be pleased if Newsom or someone like him became the nominee, which would make a Trump defeat even more likely. But Biden's not about to step aside, and regardless of any shortcomings, he's head and shoulders above Trump based on his record and his lack of Trump's innumerable disqualifying faults.
Today, I read an account of the multiple instances where Trump has shown how unsuitable he is to serve as Commander-in-Chief, including the time he chided Milley for bringing a wounded solder to an event and his characterization of POWs as "suckers." It's remarkable that Republican politicians ignore all this and line up to kiss his whatever.