I don't think so. Biden after four years in office is far worse off cognitively and physically. I think he's going to have a hard time spending an hour on a stage debating anyone. Newsome is too oily to be the alternative. He's too obvious as a Leftist candidate and that will be too much baggage for the nation as a whole.
The Republicans have viable alternatives to Trump. The Democrats have backed themselves into a corner and are stuck with Biden. If Biden doesn't face Trump, he's pretty much done. In a Trump-Biden match up, it's really a toss up who will win at this point.