Justice League Dark: Apokolips War is not how the universe is supposed to end. There must be something after the flashpoint. The New Gods Of New Genesis and their planet must have an appearance.
Justice League vs Parademon League is a direct sequel to Justice League Dark: Apokolips War and shows something after the flashpoint.
That Darkseid in Justice League Dark: Apokolips War is just his clone. Darkseid revealed it in this proposed movie.
After Henshaw got free from Darkseid's brainwash, Darkseid wanted a weapon more powerful than the others, a clone of himself. Using the Mark of Skath, Darkseid makes his clone. Weeks later, he heard the Justice League making plans, and realized that it was not enough for his clone to succeed, because the clone was too small, so he made improved Parademons called Paradooms. After that, Darkseid left Apokolips in a giant spaceship. Moments later, the Paradooms and the Darkseid Clone defeat the Justice League when they arrived. The weapons succeeded for two years until Superman and Trigon fight the Darkseid Clone, and Cyborg opens a Boom-Tube which pulls the Darkseid Clone, Trigon, and most Paradooms into the black void.
Before the Flashpoint, Darkseid stays in another universe to get more resources until the flashpoint in this universe ends.
After the Flashpoint, Darkseid returns to this universe.
Darkseid used The Parademon League, each Parademon with different powers according to the hero it fights against. These were The Justice League from another Earth, captured and mechanically modified into Super-Parademons by the Female Furies of the DCAMU using the Worlogog. Darkseid reclaims the DCAMU Earth after the Super-Parademons defeat The Justice League of this universe, But Damian Wayne escaped from being brainwashed. Darkseid then tells the Elite to use the Worlogog to get many items to rebuild Apokolips.
Damian calls Red Star, Kole, Gnarrk, Jericho, and Argent, Pantha, Hot Spot, Bushido, Wildebeest, Herald, Kid Flash (Wally West), and Jinx to help him take on Darkseid. Kid Flash frees the Justice League while the other Titans battle the Paradooms. Orion and Scott Free, sons of Highfather, battle Kalibak and Grayven, sons of Darkseid, but Scott Free was eaten by some Paradooms. Orion was able to defeat Kalibak.
After the Justice League Defeat the Parademon League, they take on Darkseid. However, Three kid superheroes, Melvin, Timmy Tantrum and Teether, approached the fight. Timmy calls Darkseid Uxas Roth and it makes Darkseid mad. Darkseid kills Timmy Tantrum using his omega beams, triggering the battle of the Justice League and Honorary Titans against Darkseid. Batman realized that he has a motherbox and he can send Darkseid to the same void Cyborg sent the Darkseid clone, Trigon, and Apokolips to. As the Honorary Titans try tried to distract Darkseid, Darkseid mutters "Begone" and blasts them with his omega beams. Argent and John Stewart soon take out Darkseid's left eye as the heroes continue to distract and hurt Darkseid. Darkseid got fed up with the distractions and uses his telekinesis power to throw all heroes to the ground. The Anti-Monitor then appears and fights Darkseid. Darkseid was able to kill the Anti-Monitor. However, Batman successfully activated the Motherbox and the Boom Tube starts to pull Darkseid towards it. Darkseid tried to escape, but Superman punched Darkseid, sending him to the black void.