The 2016 election was not about the economy and the 2020 election won't be either
Despite massive media-driven attempts to gaslight us about this, people did not turn to Trump out of economic worries. In 2016, Hillary Clinton won voters who listed "jobs" or "the economy" as their chief concern by 12 points. This was the same amount by which she won voters from the poorest half of the population (household income of $50K or less). The economic cohort Trump won most strongly was people in households making between $75K and $100K.
The problem was there just weren't enough voters who were concerned about the economy, because the economy was pretty good, and it's even better now. Barring a downturn, there will be even fewer economy voters next year.
What happens when voters don't have huge economic anxiety? They start worrying about stupid shit. Trump won voters who listed "immigration" as their chief concern by 30 points.
There's an interesting graph Pew sometimes does when they ask voters what their top concern is. They allow free-form answers and then group them into subjects. They then divide a square representing all the voters into a bunch of rectangles representing the issues they care most about. So, if half the respondents said "crime" and the other half said "jobs", they're draw a line down the center of the square and you'd have two equal sized rectangles. The interesting thing is that when you go back historically, Presidential elections with one big rectangle a ton of small rectangles are won by Democrats: Presidential elections with a bunch of more or less evenly sized rectangles are won by Republicans. When there's not a specific overwhelming problem to solve, voters don't mind letting Republicans do stupid shit.
Here's the bad news: there is not currently a specific overwhelming problem to solve. In 2016 Trump said everything was terrible and we needed radical change, and like idiots we ran with that framing ourselves and managed to hand him a "change" election with 4% unemployment. He's not going to do that again, and he's not going to run with our framing like we did with his.
The simple fact is this is as good as the economy has been in any living Americans' memory (yes, better than even the gilded 1950s), and it's going to be hard to convince voters otherwise (and the voters who are not enjoying the benefits of this economy, again, already back us by double digits).