the film with June finding the artifact that held Enchantress but they changed it and made that a flashback. Maybe there was more of Enchantress cut.

But it really wasn't that complicated. She wanted revenge for keeping her entrapped. When she summoned her brother she said that humans don't worship them any more and worship their machines, so she would destroy our machines/technology. She got her heart back from Waller and started destroying ish.

Again, she wasn't really fleshed out. It would have made more sense if the movie opened with Juin finding her and then the flashback could have been to thousands of years ago when she was entrapped, because then the revenge motivation would have been clearer. I also don't know if her plan was to straight up destroy us or to just destroy our technology to make us worship her. But I can put two and two together and I have no knowledge of her character from before this, never read any comics, etc.