Most Americans are unaware of the checks and balances in our electorai system. There was a time when a large city "boss" might be able to put his thumb on the scales and produce the outcome that he wanted, but doing that today would be exceedingly difficult. So yes: we still have overall election integrity.
But I am concerned: we have a growing number of people--including prominent political leaders like Mike Johnson--who have openly said that they want to replace democracy with something else (in Johnson's case, a theocratic Republic).
Was Trump's win legit? Yes. No one has brought forth any credible evidence to suggest otherwise . (I am not saying that I support a system in which an archaic body like the electoral college is empowered to override the will of the majority--but that is the system that we have, and within the rules of that system, Trump's win was legit.)
Was Biden's win legit? Unquestionably ... the three individuals in the best position to judge (the attorney-general, the FBI director, and the director of cybersecurity within the Department of Homeland Security--each appointed by Trump) all denied that there was any significant voter fraud or irregularity. None of the fifty state officials responsible for the oversight of the election within their states have come forward to question their results. The Trump campaign and allies filed more than sixty lawsuits in an effort to overturn the results in one or more states--and they ultimately lost everyone of them. This is not a close call, and it isn't simply a matter of opinion ... the evidence here is overwhelming.
Will the 2024 vote be free and fair? I think the odds are good, The worst of the "bad actors" running for offices (in 2022) that might allow them to tamper with the election appear to have lost. But there still people with influential positions who might attempt something--especially if Trump loses again.
Mail voting and absentee voting have a long history in this country and very few states have reported any abuses associated with these methods. The notion that they were "dangerous" or easily subverted was spread by Trump in a transparent attempt to discourage people from going to the polls.
Conventional wisdom tells us that when there is a high turnout in an election, the Democrats do well--but if the turnout is low, the Republicans will have the advantage. Trump simply wanted to suppress the vote to benefit himself.
