The tone of the message can be adjusted per candidate, but I really feel like a "seriously, what have they done for you?" campaign could gain traction, especially in areas that have been red for a while.
"Have you gotten a raise? Are the roads around you fixed? Is your kid getting a better education? The only thing they've been really successful at is getting you to hate your neighbor while ignoring the stuff that really matters."
The Republicans will always win the messaging battle when it comes to culture war shit. The Democrats shouldn't try to fight them on it, nor should they ignore it. What they need to do is redirect the conversation to highlight that all the Republicans do is focus on the Facebook issues instead of the real ones.
Might be blasphemous to claim this on the internet but MOST people don't want to go around hating everyone. Giving everyone a common enemy: "these guys are the reason you are mad all the time because they keep focusing on what divides us instead of the shit that actually matters" might have surprising staying power. It isn't a naive message of kumbaya either, it's a "yeah we might have different views on some stuff, but let's focus on keeping you employed instead of the genitals of high school athletes in Tennessee."
I just really think there's a lot of people tired of feeling like they are constantly in a culture war.