This isn't anything reflective of the timeline nor changes I will ever make, but my take on how DCEU's Flashpoint split the universes - when restoring hope to a world devoid of it, Superman's death was undone in the DCEU and thus what was once the consequence of that, the Suicide Squad's history and general purpose, occurs on another Earth with a new history/purpose encompassing it. They never existed in the DCEU now.
So, what's canon after Flashpoint?
DCEU (Earth-1):
- Man of Steel (ALTERED; an older Bruce means a Batman with a different history and potentially different outlook on life, thus Zod likely never got as far as he did assuming Clark had more help and less BS. Perhaps a League began long before 2017 in the current timeline.)
- Wonder Woman and Wonder Woman 1984
- Aquaman and Aquaman and the Lost Kingdom (slightly-ALTERED; He never fought Steppenwolf, that along with BvS are erased)
- Shazam and Shazam: Fury of the Gods (slightly-ALTERED; BvS and JL events never happened so forget any references to them happened in the current timeline. Economos and Halcourt can still have their DCEU dopplegangers with no Suicide Squad. NOT Rick Flag, however, more on that in a minute.)
- Black Adam
Blue Beetle is arguable. It either happened in both, or Palmera City's LexCorp is a regional subsidary of LuthorCorp. That post-credits scene with Ted Kord did NOT happen in the DCEU, if it will matter in the DCU down the line.
Now the DCU's canon starts with Creature Commandos but what is
adjacent?
Simply,
Suicide Squad's existence and basic history. However, the 2016 film is non-existent, non-adjacent and meaningless. No Jared Leto Joker, period. Margot Robbie's Harley Quinn is a question mark, but if she exists in the DCU then in my headcanon roughly quite a bit of Birds of Prey might have occured as well - but far,
far more differences than Gunn's The Suicide Squad and Peacemaker season one.