Earlier quoted context omitted.
Before 2016, polls were much more accurate. And paper ballots were the norm. So there's that.
? A huge percent of ballots this year were mail-in, and all paper. And the polling error was worse in 2020 that 2016.
I might also target only key locations--those on the margins where it wouldn't be suspicious.
If I were to do this in favor of the Republican candidate, you'd probably find that mail-in votes even in non-pandemic years skewed more Democratic. You'd also find that polls seemed to indicate that Republican voters were "shy" and it keeps messing up the polls.