I think there’s a difference between knowing but not caring and not believing it. I know plenty of people who support Trump despite his awful history but I also know plenty more who thinks all the bad press is a lie.
This doesn’t absolve them in any way but you’re not gonna change anyone’s mind in the latter camp by telling them “you know he’s bad, you just don’t care”. And before you say it’s not worth trying, I successfully convinced two different coworkers who voted Trump in 2016 to actually look into the accusations and both voted 3rd party in 2020