Given that Blacks, Latinos and women voted more heavily for Trump in 2024 than they did for Biden in 2020, and that White men voted more for Harris than they did for the Trump in 2020, can it be said that all four demographics voted against their own self-interests?

Only true if you believe it is in White males' best interest to preserve the White patriarchy.

That said, my overall conclusion is that people generally voted for the person who was best going to help them personally and not for the greater good, which would have meant more votes for Democrats.