I am hearing this circular argument all over the place
The thesis is that Trump will look like he has a landslide on election night via post-election polling but the mail in ballots will tilt back over to Biden and this could create a political/information vacuum
Surely the American election system accounts for this and you have a deadline of mail-in ballots to arrive and at X time on X days after the election the winner is declared
My initial thought process is that the Dems are flooding this propaganda as information warfare to prepare to essentially coup the government and throw Trump out even if he wins (which I think will be likely)
I pointed to other user how the Dems spent 4 years on a Russia-Gate hoax than address why Clinton lost the election (everyone hates neoliberalism)
I think you underestimate how entangled the Democrats are with the State and the damage they have caused Trump on completely falsified conspiracy theories (like russia-gate which has since been disproven since Mueller took a dressing down)