At the end of the day all it amounts to is "what if there was an evil wizard who could wave his wand and blow us up?!"

It's silly nonesense. How are you going to "hide" from the imaginary wizards who can blow up galaxies? Whatever silly star trek space magic they have is operating on levels of energy manipulation that are impossible per physics as we understand them. You're basically picking a fight against an atheist thought experiment used to convey how silly theism is. "What if Russel's Teapot and the Invisible Pink Unicorn got together and decided to beat us up? What would we do?" You wouldn't do anything, because there's no serious reason to believe those entities do or could exist, and if they did there still wouldn't be anything to be done about them.

Even the assumption that you could take any deliberate action to hide from them. If we're the ant hive risking destruction in this grand cosmic play you're saying we should try to avoid detection from imaginary enemies armed with things as incomprehensible to us as satellites and electron microscopes and gravity wave detectors are to ants. Since we're trying to protect ourselves from imaginary space wizards with impossible powers one can play along and suggest that the imaginary space wizards have equally potent methods of detection - crystal balls, scrying pools, magic mirrors, and so forth. And these methods of detection would render our attempts to hide from them just as pointless as our attempts to combat them in open battle.

It's all silly. Maybe there's a very large man in the sky who will be cross with us and punish us for being naughty. Maybe there is! So what? We can't see him, interact with him, communicate with him, or kill him, so why worry about him? We can't even guess what method he might use to perceive us.

Have you read Alastair Reynold's Revelation Space? It tackles Dark Forest, and all of these questions you're raising, from what I found to be a much more creative, imaginative, and thought provoking perspective. It's just as full of silly space magic as TBP, but the space magic is at least somewhat grounded with some rules that keep things modestly comprehensible, the characters are much better written, and the premise is more interesting than just "what if game theorists weren't silly asses and were right?"

I hadn't realized how much Dark Forest is the same kind of silly bs as "Roko's Basilisk" until you laid it out here. It's just another tech-bro formulation of Pascal's Wager. It's not even a thought experiment because the answer is always "there's no useful action we could take so we shouldn't waste time worrying about it." That's the whole thing with true unknown unknowns and outside context problems - you cannot, by definition, prepare for them.

We could at least conceivably work on systems to defend against rocks flying around in space. Rocks flying around in space actually exist, they're a known problem, they're not magic, we can see them (or we could) and we could build machines to nudge them away from the planet if we really wanted to.

But the Dark Forest concept isn't meaningfully distinct from sitting around saying "what if God was real and he was really, really pissed at us?"