James Gunn has shared with Rotten Tomatoes his rationale for switching over the Justice League to the Justice Gang in Peacemaker season 2, as he also recalls that there was really no one in charge of the DCEU at the time that he was making the first season of Peacemaker.
Back in 2017, Zack Snyder stepped away from directing Justice League and from his broader role overseeing the DCEU due to a family tragedy. Joss Whedon was brought in to finish the film, but no one was ever appointed to take on Snyder’s larger responsibilities of guiding the franchise.
Later, Dwayne “The Rock” Johnson and his team attempted to position themselves as the new creative force behind the DCEU, but that effort collapsed following the box office failure of Black Adam.
Circling back to Peacemaker, below you can watch Gunn briefly touch on the fact that he was able to make the first season of Peacemaker without anyone standing over his shoulder and how there were loose plans to reboot the entire DCEU with The Flash.
"Peacemaker was always in a weird place. People say he was part of the DCEU but he wasn't really. He was part of this "in-between Universe" of DC when there was nobody really making sure that everything was connected and at a time when they were going to rewrite everything with The Flash. We were kind of able to do whatever we wanted and we had that brash ending, which I loved, it was one of my favorite things from the whole season, but it just didn't fit in with the DCU. And Peacemaker, there's hardly anything else that you need to change for him, he can slide very easily into the DCU, same with Blue Beetle. They just kind of fit in very nicely, we just have to retcon a couple of things."
It’s certainly reassuring to know that Blue Beetle is still slated to make the jump into the DCU. Widely regarded as one of the stronger entries to come out of the DCEU, the film unfortunately suffered from poor timing as its release came after it was already public knowledge that the DCEU was ending, which dampened overall fan enthusiasm.