All of this posturing is dumbass stuff at its worst: "If you don't vote for the guy you're supposed to, we won't either, mmmmmm ... K?"
The only people who've announced they're going to do this are Democrats, whose EV ballot envelope might as well say "LOSER" in big blue letters. Not a single Republican has announced so much as a hypothetical interest in this laughable "plan."
There was a Florida Republican elector that said he won’t vote for Trump.
He announced his resignation, and will be replaced by someone who can.
...but I think that’s it.
Trump’s electors are loyal to Trump. The failure of an elector to vote for the candidate who picked him for a slate never happens because he knows what side his bread is buttered on.
The main reason for the lack of events where an elector votes for someone else is simply because, for example, Trump supporters chosen to be electors will tend to favor Trump to a very high degree - as you post in your first sentence.
Posters don’t seem to get that electors are not faceless random people.