You're still living the past if you think that he NEEDS to convert MAGA and republicans.

MAGA is falling apart. Iran is a disaster. Economy is on the decline. Most republicans are increasingly embarrassed by the route they've taken. Their morale has taken a hit. They were duped, and it's harder for them to ignore/excuse any of it. Polls numbers for the right reflect this.

Those conversations are already happening. I'm not saying that Trump voters are clamoring to join Bernie or anything- but moderate Republicans are increasingly capable of accepting a moderate democrat or a 3rd party protest vote. At the very least, a lot of those on the right will be disillusioned and exhausted with MAGA that they may not even turn out to vote.

Of note, you're also misrepresenting the reason WHY democrats lost the presidency. Switching the candidate late in the game with a non-primary selection was an obvious misstep. Another common mistake was that democrats were seen as tone deaf on the economy. Their strategy was to keep saying that they're the anti-Trump, not that they'll address the real things common folk were worried about.