What evidence? An accurate statement might have read, "Despite the lack of conclusive evidence, nearly one-third of Americans still believe the 2020 presidential election was stolen".
>You can really only prove this type of thing in a single direction, by providing evidence that there was fraud on such a scale as to have swung the results.
This assertion relies on the baseless assumption that the elections are fair unless proven fraudulent. Given the history of elections the opposite could just as easily be argued. This is one of the most important reasons to have total and complete transparency on every level of an election with an auditable paper trail that can be publicly scrutinized leaving no doubt about the integrity of the election among any honest arbiter.
Personally I have doubts about the integrity of every election in my lifetime, and I'm not a young man.