Trump won the US presidency by winning the popular vote in the right states (like all other presidents), not the national popular vote. Unlike most presidents, he lost the popular vote, and won because the electoral college picks presidents somewhat close to the popular vote though by bigger margins most of the time. Let’s say Trump lost by 5-6 million votes and turnout was 67% of the VEP (it was 60% last time, that is not relevant other than context on size and percentage).
Note: this is NOT intended to be a projection/prediction, just a hypothetical like many of the other questions.