I think the environment, overall, is definitely in Biden's favor. But I don't think it's anything close to guaranteed. The polling might have been corrected some since 2016, but the wild cards in 2020 are so numerous and complex that we can't possibly expect the polls to be a good measure of who will actually vote, how they will vote, and which of those votes will be counted.
You're right that the polls in different states are correlated, but that actually undermines your point. It's not likely that PA polls will be uniquely off - it's more likely that systematic factors mean that all of the purplish Midwestern states are shifted one direction or another due to the aforementioned wild cards.
If you asked me to put money down on the victor, I would definitely put it on Biden. But just because he's the most likely victor doesn't mean I have a great deal of confidence in the outcome - even assuming there aren't shenanigans wrt not counting mail in ballots.