So, you like do understand that that is exactly how DC comics has worked for like 8 freaking decades RIGHT?
there's a reason they created earth 2, earth 3, earth S, earth X. Why they have had constant retcons like COIE, Infinite Crisis, Final Crisis, 52, Flashpoint, Rebirth. Hell if I went on to list the retcons done within titles between dcu wide returns the list would be several paragraphs.
The fact is they made a release back in 2014, three years before JL stating that their movies would not limit creative talent to fit a merged universe. It was restated in 2018. Anyone who expected DCEU films to fit with each other completely and not have contradictions or alternate continuity had an unrealistic expectation from the beginning