You can play with the electoral map here.
If you look at the high quality polls at 538 (e.g., those with A-range ratings), Biden is at best slightly ahead in Florida, North Carolina, and Arizona, states that often land in the Republican column. If those polls are missing anyone, it is surely Trump voters: folks who believe in QAnon aren't going to be talking to pollsters one suspects. So let's assume the missing folks all vote Trump, and Florida, North Carolina and Arizona go for Trump again.
Forget about Ohio and Georgia: those polls sometimes show Biden up by a point or tied, but mostly show Trump ahead. If Ohio and Georgia really go Democratic, then we're in Biden landslide territory, but I doubt it's going to happen (in part for reasons that some Trump voters reveal here: that Trump is a bad person isn't enough reason to vote Biden if you basically like Republican policies. As in 2016, the Democrats are counting too much on "Trump is an awful person.")
So if all the frequent or typical Republican states vote for Trump, that means all Trump has to do is to recapture one of the states he won in 2016. The best bets are Wisconsin and Pennsylvania: although Biden leads in both, the lead is not as strong as in Michigan (and nothing like his double-digit leads in places like Virginia). If Trump flips Wisconsin, then no one wins the electoral college, and oh boy are we in for a nightmare (then, as I understand it, everything will turn on whether the Democrats capture a majority of states in the House of Representatives). If Trump flips Pennsylvania, then he wins the electoral college, no matter how many millions more vote for Biden in California, Illinois, New York, New England, the Pacific Northwester, Colorado, Minnesota etc.
On the other hand, if Achen and Bartels (Democracy for Realists) are right, then Trump should lose in a landslide because of the pandemic and the economic carnage. We'll find out soon enough.