We are in historic times (every presidential election is historic) and people often try to draw comparisons to history. I’ve seen several that are wrong.
First, Biden in his statement the other day said he would be the 4th person to defeat an incumbent president. In fact, if he does prevail, he would the 11th. I think he probably misspoke - perhaps he meant 4th “in his lifetime” or “since WWII, both of which would be true.
Then, Nancy Pelosi states that Biden, if elected, would have a bigger mandate than JFK. True enough, I guess, but JFK won by one of the narrowest margins in history (in fact, there is an argument that he actually lost the popular vote).
Third, I saw the statement made (can’t remember by whom) that Trump will be the first nominee to lose the popular vote in consecutive elections. Not true - there are five others including two, JQ Adams and B Harrison, who like Trump, won the electoral college the first time.