More people voting shows at least an interest in politics. There are many more ways to manipulate the outcome of votes, by suppressing votes from certain populations and gerrymandering. https://www.brennancenter.org/our-work/research-reports/gerrymandering-explained
One of the extreme examples of voter district manipulation:
With the rise of AI you can use software to group people together that vote one way, to get them out of the way in other 'districts'. It's how many districts you win, not how many votes you get.
All because of the "winner takes all" system. That's how Bush (2000) and Trump (2016) won the election despite losing the popular vote.
https://www.history.com/news/presidents-electoral-college-popular-vote
(Not that Hillary Clinton would have been any better, what a snake she turned out to be)
Voter fraud wouldn't surprise me either, the whole system is corrupt. Yet a 66.2% turnout is nothing special and still puts the US behind most European countries
https://www.pewresearch.org/short-reads/2022/11/01/turnout-in-u-s-has-soared-in-recent-elections-but-by-some-measures-still-trails-that-of-many-other-countries/
Problem is, thanks to "winner takes all" and manipulation of voter district boundary lines you don't need to mess with many votes to turn an election.
Essay Pro