As a foreigner, I'll just note that I haven't seen a US election without ballot/machine issues, or the widespread fear of issues, in at least 20 years - every time the losers have talked about structural election issues like ballot harvesting.
The problem is that the desire to fix this is entirely partisan and the party in power always mocks the other party, even if this was their issue for the last cycle.
The USA has a problem. The process (of voting) isn't just supposed to provide an answer, but an answer you can trust. There's no transparency in the process and if people ever do ask a question ("why was that seemingly extra bag of ballots pulled out of a closet at 1am?") they get mocked as idiots who don't intimately understand the process.
Looking at the process of voting and counting in the USA there are a lot of things I'd fix to make the process more visible. In any industry where people monitor workers by video (casinos especially) they have them work in very standard ways, hand motions, card locations, etc, all chosen to make cheating hard and easy to detect.