I feel like the current iteration solves an interesting dilemma in writing for Superman, how do you deal with him being so overpowered over humans?
In this case, there are existing power structures in place that can fight Superman. Hell, there are existing power structures that can replicate what Superman does and these power structures are threatened by Superman.
I think the population, as a whole, can get dropped into a super hero saga in media res. You don't need an origin story for the universe any more.
In regards to #1, Antifa isn't sold as an "antifascist" organization to the MAGA crowd. It is sold as a "leftist" organization that participated a lot in the BLM protests. This is sold as a big scary group that will make America a bad country.
If you aren't steeped in right wing media, you wouldn't know of this organization because this organization doesn't exist.