I don't know the exact number, but afaik less than 1 million. Compared to the size of the electorate, a few hundred thousand votes here or there is really not that much. It only seems so to Americans because they have historically low participation and high polarisation.
Also, turnout set a 50 year high in percentage of eligible population to vote.
The only people who think this election was “close” are the same ones who keep saying that shocking new evidence will be released tomorrow by Giuliani, but only if I send in a check to the committee to save America.
Losing as an incumbent is humiliating, doubly so when you get rejected by so much of your own party. Trump’s loss was a humiliation, particularly because it was because he was such an incompetent president.
What was the minimum number of votes across the minimum number of states needed for him to win in 2020? Again, nobody has actually provided a reason this vote was close - it wasn’t close at all, it was a humiliating rejection, especially for an incumbent.