I had a crazy theory about the Rebuild movies, reading this:
https://forum.evageeks.org/thread/14454/Theory-about-Kaworus-intentions/SPOILERS
So one theory is that the Rebuild continuity is a sequel to Neon Genesis Evangelion, possibly taking place after The End of Evangelion on the same Earth... somehow. Red oceans, blood streaks on the moon, etc.
There are various points which seem to contradict it being a literal sequel on the same Earth, but it's possible those have an explanation too... Things like, uh, the entire Earth being "reset," everyone's memories and all, with a different version of Second Impact being depicted with four Adams instead of one like in the original show.
Eva 3.33 ends with Kaworu getting tricked by Gendo and starting Fourth Impact. Kaworu says "we'll meet again, Shinji" before HEAD ASPLODY. He also calls Gendo "King of the Lillin (humans)."
Gendo for his part betrays and murders the entirety of SEELE in this movie, depicted as basically servers/monoliths. But they don't care! "Our goals are accomplished. We wish for the peaceful purification of all souls."
I theorize that Eva now exists in a continuity-loop somewhat like how there were six versions of The Matrix and The One (which we didn't know about before Reloaded), and the Rebuild is the one where things actually change and the loop is broken.
I also theorize that these continuity loops are orchestrated by Gendo and SEELE, each one trying to one-up the other each time. SEELE knows that even if they "fail" in this continuity, if they've accomplished things that carry over to the next continuity reboot, they'll win overall.
As a potential contradiction, Fuyutsuki implies things are still being orchestrated by Yui in 3.33. Not sure how that could play into things.
Anyways this is almost definitely wrong, but I think it would be REALLY cool if Anno went "Oh you thought you figured everything out with your sequel theory? Actually there's been HUNDREDS of sequel Eva continuities you've never seen! What makes this one so different? Watch and find out."