I think there is plenty wrong with Democratic messaging, not their policy agenda. They never got it that throwing the types of ongoing hissy fits that Republicans endlessly do (examps = garbage comment by Biden or Clinton emails) is the most effective way to do politics in the current environment.
They could have destroyed Trump long long ago by using Republican tactics against him. But they want to talk about prescription drugs and infrastructure bills.
In any event, since Trump and the current MAGA Republican party are incompetent nuts (worse than Bush II and crew) and are probably going to destroy everything and completely overplay their hand--as long as elections aren't cancelled the Dems will almost certainly come roaring back in 26.