I don't understand how Dems run a national campaign without ever mentioning W Bush. You spend a week where all Dems talk about how the GOP puts up first Bush who crashed the economy, started an unnecessary war, supported torture. And then they follow that up with another disastrous president in Trump, who leaves us with a quarter million dead of a Virus that not only hasn't been controlled but is spreading more than ever.
You hammer on the awfulness of W Bush and Trump and the total rot of the GOP (including voter suppression). And after a week of getting that message out, then you trot out Obama to campaign for Biden. And you talk about how Biden will have to fix the country and contain the virus, much as Obama/Biden had to fix the mess inherited from W Bush.
My point is you don't just run against Trump in isolation, but you remind folks how awful the GOP has been this century, and contrast with the normality and good the Dems do (health care, environment, growing the economy).