The best thing they can do and I hope they did this, is the movie retcons a lot, even if it's off camera, you shut learn that it's a different era now, a different universe.
So moving forward, Shazam! 2 can appear as stand alone as it will appear unaffected.
Same with Black Adam and Aquaman.
So what's left - well Batman - Batman can be retconned so it was always Keaton. Meaning BvS never happened as we saw and as a result, Justice league.
There can be a brief 'oh well I didn't trust the super man but hey, I'm a detective, I soon saw he was just a boy scout working the DP, clark's ok by me!"
Which means we are allowed a retconned MOS2 and literally just wipes away JL and allows movies moving forward to move forward.
WW3 can do anything it likes, as can batgirl, supergirl, future flash movies but honestly I cannot see them bothering to do a justice league.
If anything, I can Aquaman 3 or WW3 being an epic movie that brings in heroes or maybe they are saving this for Black Adam 2 where he literally takes on everyone but honestly, I am not invested enough and I don't think anyone else is.
one more round of movies and then I can see it being called a day...