Was there fraud? Absolutely. Was it enough to change them outcome? Probably not but there’s absolutely no way to be certain.
Fraud has been a hallmark of the Democrat Party for many decades. When Lyndon Johnson stole the election from Nixon on behalf of his running mate John Kennedy in 1960, as is widely known was done by LBJ in Texas and by the Daley crooked political machine in Chicago, it wasn’t a new thing for the Democrats. They had much experience. Daley was an old hand as was LBJ and other Democrat machines.
And they didn’t suddenly stop committing fraud after stealing 1960. In New Jersey Democrat candidates were convicted of election fraud even in the last decade.