Overrated
-The age-gap. For one, Trump cut significantly into it in 2016, and the Senate races had even smaller ones (or none). Secondly, while there are more conservative and more liberal age cohorts, all do get somewhat more Republican as they age.
Underrated
-The absolute Democratic collapse with Christians (both evangelicals and Catholics), largely due to family values and abortion. If the Republicans can extend this to religious Hispanics and blacks, the Democrats will have to become socially conservative or be irrelevant for good.
LOL. Yeah, Trump, "grab them by the pussy," "if she weren't my daughter" ((family values)) GOP President. That party? Yeah, you lost that mirage the moment your party even considered nominating him.