Actually no thinking about this no no no no this is the proper way:
1- The Batman (Dick Grayson/Nightwing would be introduced much like Rhodey was in Iron Man; love interest being Vicki Vale she would be Bruce's Pepper to his Tony; villain being Ra's Al Ghul and League of Shadows)
2- Martian Manhunter
3- The Batman 2 (villain would be Bane; Nightwing has more of a central role this time around fully becoming Batman's sidekick)
4- Superman (villain would be Bizarro; post credits builds towards Steppenwolf)
5- Wonder Woman (villain would be Ares and the Nazis; exact plot of the WW film we got in real life except it takes place during World War 2; post credits builds towards Justice League with the Mother Box)
6- Justice League (The team would be
Batman- Iron Man
Superman- Captain America
Wonder Woman- Thor
Green Arrow- Hawkeye
Martian Manhunter- Hulk
Black Canary- Black Widow
Villain would be Steppenwolf, sent to Earth by Darkseid with a Mother Box to get the second Mother Box which you see from the Wonder Woman film
Phase 2
7- The Batman 3 (villain being Joker)
8- Man of Steel 2: Rise of Zod (villain being General Zod; Supergirl is introduced)
9- Wonder Woman 2 (villain being Cheetah; Hawkman is introduced as a Falcon equivalent)
10- Suicide Squad
11- Justice League 2
Batman, Superman, Manhunter, Arrow, Black Canary, Wonder Woman are back; Zatanna is introduced as a Scarlet Witch type character; Flash is introduced too as the Quicksilver but Flash dies in this film; Cyborg also introduced as the Vision of the team; villain being Doomsday)
12- Atom
Phase 3
13- Batman vs Superman: Dawn of Justice (villain being Lex Luthor as the Baron Demo of the DCEU; turns the JL against each other; JL breaks up into 2 separate teams like Civil War
Batman's team consists of himself, Nightwing, Cyborg, Black Canary, Aquaman introduced as the Black Panther of the DCEU and Shazam introduced as the Peter Parker/Spidey of the DCEU
Superman's team consists of himself, Zatanna, Green Arrow, Atom, Hawkman and Supergirl who would fill the Bucky position quite easily
14- Dr Fate
15- Suicide Squad 2
16- Shazam (Batman would be in this film as a mentor to Billy; villain would be Dr Sivana and the Seven Deadly Sins; Shazam Family would also be introduced too)
17- Wonder Woman 3 (Martian Manhunter would show up more or less in a post credit scene which would usher him in back to warn Diana about Darkseid)
18- Aquaman (villains being Black Manta and Orm; 3rd Mother Box shows up in this film builds towards Darkseid)
19- Justice League 3: Part 1 (Darkseid)
Invasion
Batman
Superman
Wonder Woman
Martian Manhunter
Zatanna
Cyborg
Nightwing
Supergirl
Black Canary
Mera
Shazam
Dr Fate
Hawkman
Suicide Squad as the Guardians
20- Atom 2
21- Green Lantern Corps (Hal Jordan is the key much like Carol was)
22- Justice League 3: Part 2 (Invasion Continues)
Hal this time gets into the fray but then so does John Stewart as well as other heroes; it all ends
23- Shazam 2
