I know how Darkseid has omega beams that track their targets, cause someone to have never existed, and trap people in a series of alternate realities they die in, and they have to be resurrected in a new reality which they die in a worse and more painful manner.
I also know that Doomsday and the Doomslayer comes back to life with immunity to the thing that killed him the last time.
I also found out that Trigon can manipulate matter, change time, warp universal forces, and reconstruct reality.
These abilities make these villains incredibly dangers and formidable, so it would be very awesome and beneficial if Darkseid and Trigon were permanently killed, and Doomsday and the Doomslayer were permanently exiled to the Phantom Zone. This way the heroes won't have to deal with these terrible, formidable threats.
I found out that Darkseid's death caused imbalance in the universe, but the writers can change it to make it that his death won't cause that. Mongul or Brainiac can replace him as the villain the Justice League fight together. either of them would definitely be a good villain for that.