An illusion of eternity is not eternity. We aren't talking about a trickster being. We are talking about a real Wizard of Oz, not a puppeteer behind a curtain. A being that gives the illusion of eternity is not the God that theists claim exists.

What is the difference? In my scenario existence is an illusion, reality is an illusion. An illusory eternal life is as good as anything one can hope for, and hope is also an illusion. In this scenario, we are all illusory beings.

I remember an episode of StarTrek where the holodeck character Professor Moriaty became self conscious, he held the crew hostage demanding that he be freed to explore space. In the end they tricked him and his lover into an electronic circuit where they could explore eternity forever. It was an illusion but it was as real as an illusionary being could possibly experience, so Captain Picard did hold up his end of the bargain. It was the best offer the Captain could make and Moriaty could possibly get, there was nothing shady about it.

Finally, a cyber-programmer isn't an ultimate creator. It's not a "necessary being" it's not an "uncaused cause", it's not a "ground of being", it doesn't inject a transcendent soul into a zygote.

We aren't talking about beings that could convince believers that they are god, we are talking about beings that have the attributes that believers believe in.

But you know that stuffs like "uncaused cause" were not even part of Christian theology until theologians clumsily trying to attach Christianity to Greek philosophy.