The entire Republican party is behind him. There are some irrelevant people who still have something they think of as principles, but they're few and far between and they fold easily. On the other hand, the democratic party can't decide what the fuck it wants. You've got 99% of the republican party saying "Trump is the greatest thing ever" and more like half the democratic party agreeing on any one thing.
He's already been president and the entire country didn't explode so he's already theoretically got more credibility than anyone in the running except Biden.
"Someone literally shot me and not only did I not shit my pants I was barely even hurt" is pretty much the biggest vibes-based victory you can get

I don't think it takes someone especially good to beat Trump, but I think that unlike in 2016 you actually have to be trying.

Theres already polls showing her either winning or performing better than Biden in the swing states and thats before she's selected and had time to actually build herself.

Personally I think her odds will go down the more we see her, not up. I think if they really want Kamala to be president they have to have her pull a Sleepy Joe and literally hide from the public as much as possible.