Bunker Baby is very upset about the very unfair polls
By 
[Note that this super professional analysis from a highly respected pollster contains an assertion that 33% of voters in the 2020 election were Republicans.]
Save for one factor, I would fairly confidently predict that if Trump is facing a blowout loss — in the context of contemporary American politics this would mean a ten-percentage point popular vote defeat — he will simply quit the race at the moment that would do the most damage to the Republican party (one very strong pattern with Trump is that he will always betray his allies/lickspittles so as to cause them the maximum possible personal damage).
That countervailing factor — and it’s a huge one — is that he’s likely to delude himself into thinking that all the data showing that he’s going to get humiliated are a product of fake biased news etc. If not for that, I really don’t think he would hang around all the way until November 3rd, if it looks certain to any rational observer, as it may well look in October, that he has no chance. Everything a malignant narcissist does is ultimately done in fear of the possibility of public humiliation, and getting trounced in the election would absolutely qualify.
This isn’t at all comparable to 2016, when he more or less stumbled into the plot of Springtime for Donald: Trump didn’t expect to win the presidency, and in many ways didn’t even want to win it. His whole presidential campaign was all a massive publicity stunt that went off the rails.
I do think the odds are excellent that, if Trump loses badly, there’s no way he makes it all the way to January 20th. He’ll issue pardons to himself and everybody in a position to rat on him, then have Pence or whatever cipher Pence has been replaced by do the same after Pence/Haley/Cotton/Arpaio/Hannity/whoever assumes the presidency, just to be on the safe side.
Yes it’s a long way to November, complacency is bad, voter suppression is real. etc. But right now Trump looks like the biggest loser, and, given his history, I doubt he’s going to play the end of the world’s all-time worst reality TV series straight.