The reason Trump and Republicans lie about election fraud doesn't hold water is shown in this statistic: More than 230,000 polling places were used in the 2018 general election, according to the 2018 Election Administration and Voting Survey.
That makes it hard to do enough voter fraud to have any effect on an election, and voter fraud will get you a vacation in a federal penitentiary. These poll workers are volunteers from the community, and it's doubtful that they would be part of a mass conspiracy.
Before I aged into mail-in ballots, I would go to my polling place and show my voter registration, sign a book with the name of voters from my precinct and vote. There is not, nor has there ever been, a need for all the BS coming from the far right about voter fraud.