Speaking of 'shy supporters', have you considered what's going on in Florida? Trump's "It's OK if some old people die, so long as the stock market goes up" seems to not be super-popular with older voters (you know, the ones Trump is OK with letting die) and he's been losing the elder vote there. BUT, have you seen any reportage of what happens when someone puts a Biden/Harris sign on their lawn.

At least in Florida, if there are 'shy voters', they're shy Biden voters.