There were something like 155,000,000 votes cast nationally. It'd be impossible for there not to be some mistakes. But it boils down to percentages. The amount of mistakes were infinitesimal.
The Director of Cyber Security, a Trump appointee and Republican, said this was the most secure election in history. Then he was canned. Hmmm. There's been zero evidence of widespread fraud. This notion that there was is purely gaslighting. Ironic this was telegraphed months before the election as if someone's backup plan for losing was to play this card.
I'm not sure how people come to choose to believe a documented pathological liar with a vested interest in continuing this charade over poll workers, judges, legislatures who certified the results, and the Supreme Court. The mental gymnastics to do so are Tsukhara-esque. It's actually insulting to everyone who worked to make sure this election went off under extreme circumstances i.e. covid