I think the majority of the Berniebots will vote for the eventual Democrat nominee, but a good many will stay home and a few may vote for Trump. They have to be furious knowing the Democrat establishment, with help from their media allies, were pushing a clearly mentally deficient Joe Biden over their guy and succeeded!
I agree with your conclusion but think of the big picture here. Berniebots are the hardest of hardcore progressives and the backbone of Democrat voting. If their support of Biden versus President Trump is eroding, what does that say about the more moderate Democrats? The polls showing a lack of enthusiasm for Biden among Democrats suggest that his support is eroding in this larger group, too.