Venat even describes herself as a "supreme deity."
She did not want to become a god for praise or worship. She wanted to become a god so that humanity would be shaped by her hand. The same motivation Athena had. They both believed humanity was imperfect and needed to be fixed. The only difference between them is Venat succeeded in reshaping humanity to what she deemed superior. She won. The world as we know it has been shaped entirely by her hand. There was no point in her staying alive and watching us suffer. She achieved her goals. Her legacy was secure. Why you're assuming she wanted to be a god for praise or worship and not to have complete, unilateral control over the fate of the star, which she did, is beyond me. She did what she set out to do. We're her strong little sparks. And now she can peace out never having to live in the world she created.
As for Emet-Selch destroying the Ancients by not letting Elidibus kill us. What? At that point he has recovered the memories of the future Venat never told him about. He knows it's already a lost battle and that his people will be returned to the lifestream to be reborn into the world of Venat's design. All he's doing by snapping us out of the void is sparing Elidibus any more fruitless suffering, because unlike Venat he actually does care about the suffering of people. He doesn't want to. He wishes he could be as ruthless as she is, but he just isn't. Allowing Elidibus to kill us doesn't mean that the world is restored to how it was. It means that Elidibus must continue to labor alone for thousands of years attempting to restore his world and he doesn't have all the information needed. What you're witnessing in that moment isn't a betrayal of the Ancients or their extermination, but a surrender. Venat won. His people will be reborn into the torture chamber of her design and not the paradise of his youth.
That's what I've been saying. She spared them on purpose to ensure the rejoinings. They were controlled opposition the whole time. If you try to convince me a mother loves her children, but she takes out huge insurance policies on them and leaves them with known serial killers, I'm gonna have my doubts about that love. Like yes, the serial killers are responsible for being serial killers, but that doesn't negate the responsibility of the mother for purposely leaving her kids with serial killers, and definitely don't try to tell me she's loving and wise and simply hoped for the best. She knew what would happen.
What you're linking supports everything I'm saying. That her acts were on purpose and intentional. I even referenced you have to ignore what the producers said about their own story to come up with some of the excuses people are using to try to still read her as a good person given everything she does runs contrary to our morals.