I don't think it's really all that relevant what "approach" Harris tried, to be honest. The whole country gets its news from social media, and no one in either industry or government is even trying to prevent social media from being manipulated on a mass scale to paint weird false narratives. That more than anything is why Trump won. The next election happening in the first place (in a form where it's actually possible for either candidate to win), or who wins it if there is one, is going to hinge on two opposing factors:

How bad things have gotten in the meantime and how strong an organized opposition movement of the actual people has gotten in response, outside of anything "political" or party base
Who spends the most money and talented effort on manipulating media and social media

I'm not sure the identity of the Democratic candidate actually matters. It would be nice if it was one that was actually good and not just more center-right crap as is usually the Democratic option. But also, if someone is looking around at the state of the country right now but also needs it to be the right candidate before they'll vote not to have more Trump, that person is pretty much as dumb as a hamster (or has been fooled by a compelling sounding but astoundingly stupid disinfo argument, see second bullet point above).