Regarding anyone believing the 2020 election will be a slam dunk for Biden, I have just a couple of things to say on that:
1) I long ago guaranteed that Trump would lose in 2020, BUT, I was careful to say several times that he couldn't cheat or that aliens from space couldn't help him. well, he cheated with the seeking of help from a foreign country which brought up a long news cycle of Biden and his son Hunter that should not have been. So, no matter what happens, I will be right about the 2020 election as I was I was in 2016.
2) I will NOT make a prediction other than the one in #1 above (meaning predicting an outcome sans the cheating), BUT it looks as bad for Trump now as it possibly could at this stage. The pandemic, the economy, the civil unrest, the bleach. None of it helps him. Now we have Murkowski saying she isn't sure she can vote for him, Colin Powell calling him a liar and that he will vote for Biden, Mattis and Kelly slamming Trump. If I were a betting man (which I am not), I would put it all on Biden at this point. I don't see how any Trumper can be sure that Trump will win. There just isn't any good news for him that would support that type of optimism.
I do know this:
Anyone who continues to support Trump is either:
1) JUST stupid.
2) Racist.
There are no other possibilities.