Honestly stopped reading after they brought back Flashpoint Thomas Wayne as the villain. The Animated movies were the only thing I keep up with nowadays.
Back to the topic of the crossover. Remnant has space tech even though the world is ass backwards in terms of tech while Atlas and Vale rely heavily on dust tech and dust does not work in space. Where in hell did they get the fuel? I am pretty sure that tar and oil doesn't exist or it's so not worth the investment because they're pitch black and easily confused with Grimm Pools.
Also Green Lantern Corps exist in this universe and by extension filthy xeno life for some retarded reason. They could've just handwaved Starro into a Grimm and fucking write Jessica Cruz having the semblance of Willpower where she can transform green light to whatever she imagines, lore friendly too.