1. The DCEU is basically just a multiverse deal, think No Way Home. They have their main universe, which is where the main continuity happens, and they have their "elseworld" style movies, TV shows and cartoons. New Batman, as far as we know at this moment in time, exists outside of the main continuity alongside Joaquin Phoenix's Joker and all the terribad CW shows. However, the Flash is rumoured to mess with the main line continuity (it's based on Flashpoint, which was the multiverse event that led to the New 52 reset), potentially writing out Affleck's Batman and maybe Cavill's Superman.
2. Probably not. The big movies are always going to be rated for young teens so it's not really feasible. It's really hard to get enough adults into the cinema to make the kind of money that the big mainline movies need to be worth making. Gotta remember that it's not just kids you're alienating, but not all adults like "adult" content either. Though, I'd love if they got James Gunn to do a Peacemaker / TSS style take on a Guy Gardner: Warrior / Red Lantern movie.
Gratitude for the detailed answer. In terms of point 2, not even TV shows? I'm not even thinking in terms of money but how they see the image of their heroes and what kind of content is... appropriate for them.