That doesn't work considering Trump has nearly 20 sexual assault allegations on himself
The goal right now, as it will be throughout the entire elections, isn't to persuade voters to move from Biden to Trump. It's to persuade Biden voters to vote third party or stay home.
This was also true in 2016. Trump didn't win by persuasion -- he got 1.1% less than Romney. He won because a lot of folks who should have voted for Clinton chose to vote for Stein/Johnson or stay home.
So if you go on social media right now it's all Bernie Bros saying "I won't vote for Blue Rapist or Red Rapist" and things like that. They're trying to get to low-info young voters and convince them to stay home or vote Green.
Green voters aren't people who would vote for any Dem regardless so these aren't people that would ever have voted for Clinton or Biden--and most Johnson voters were right wingers who didn't think Trump would be able to deliver because of his divisiveness--you can guarantee those people would also never have voted for any Dem in 2020. All I see in these posts is that people know Biden is going to lose, and isn't a very winnable candidate, and are laying out the groundwork for the excuses when Trump inevitably wins (and the same tactic would've been done by the Bernie people--claim the Biden people were trying to get people to vote third party--for his eventual loss had he won the nomination instead.)
13% of Bernie Sanders 2016 primary voters chose to either stay home or vote for Johnson/Stein. If even half of them had voted for Clinton instead, she would have won a solid victory over Trump with MOV 60 EV, 5 PV.
I won't address the rest because I don't disagree, but you need to consider the context of the 2016 Bernie support--there were
a lot of hardliners that were 100% in support of Trump outside of his healthcare/education plans and voted for Bernie as a result (seems to be a thing among white nationalists for example) and other generally populists who were going to vote for whoever they felt was the most populist--not to mention a lot of crossover Republican voters that were 'stop Clinton at all cost'. Most of that number were not going to vote for any Democrat, ever, and I'll wager that a good chunk would have
still voted for Trump even if Bernie won the nomination.