Suppose you're at the top of the Biden campaign. You can see massive fraud has occurred at a level you'd never have signed off on because it's too obvious. You know about the lawsuits filed and you're pretty sure more are to come. You know the SCOTUS will rule against you and even if it doesn't the disputed states have Republican legislators. You also know if it goes to court a lot more illegal stuff is going to be found. Neither Joe nor Kamala has put anything in writing to ask for fraud, and you start to worry if the courts find it, they'll blame you and claim they knew nothing.
Now at this point, you can fight it out, have the fraud uncovered, and Trump in office. And he'll fuck your entire fraud apparatus and the party's reputation will take a massive hit and you might be the fall guy. Or, you can weasel out. Call some people, get them to find 'glitches' they can 'fix'. Up to now whenever that happens it means more votes for Joe but you tell them you're shocked by reports of fraud and that we need to root out all such instances for the good of the country. At this point, the people on the ground start to think 'Holy shit, those fuckers at the top are about to throw us under the bus' and start to unwind the fraud. Because of the generally incompetent and slipshod nature of American electoral fraud though it's all done in a much too obvious way. Just like there were massive swings to Biden in the chaos of the election day count in a desperate attempt to compensate for Trump's unexpectedly good showing, now there will be massive swings to Trump as people start to unwind it.