I think you've got that twisted. Most moderate democrats are fine with Newsom, he's a classic neoliberal. It's the hardcore progressives who hate him for still bowing to big businesses and the conservatives who hate him because fox has been teaching their bloc to hate him ever since he won the governorship.
Blue voters in the south tend to favor establishment neoliberals over progressives. Bernie did fine in the rust belt but wasn't really appealing to the southeast.
A strict constitutionalist veteran like Kelly is probably what the country needs more than anything right now, but he doesn't look a 1980s high school movie villain that every girl wants.
Plenty of "swing voters" vote on straight up feels. If they felt economic hardship under a Republican administration, they vote for change. If a Democratic administration stabilizes the economy and halts a slide into recession, that wasn't good enough and they vote for change.