I can explain the ETH in a single sentence:
"The extraterrestrial hypothesis posits that other intelligent life exists in the universe and that it sometimes sends probes/craft to our planet."
I'm with you here.
I have yet to read anything even remotely as cogent as that regarding the co-creation hypothesis, and that makes me very, very suspicious.
That's where I think you've jumped the shark a bit.
The ETH and the co-creation hypothesis aren't incompatible. I
have experienced firsthand that my perception has been screwed with on at least two occasions.
And that leads me to believe that they can effect such perceptual changes, but that my consciousness was involved in the creation - or at least acceptance of these changes.
Let me describe an encounter, but please understand it's difficult and personal for me.
One night as a teenager, I woke up as a bunch of tiny deer walked into my bedroom. I was in some kind of altered state, but in a state of wonder about it. Like "cool, somehow deer came in the house!"
They were very tiny. Like maybe 50 lbs. Big eyes that stared at you. Typical screen memory stuff.
One hopped up onto my bed and kind of sat down, just staring at me. I reached out and grabbed it's hoof. Only it didn't feel like a hoof - it felt warm and soft, more like a cat's paw.
But deer don't have cat's paws... when I realized that, the deer on my bed changed into a prototypical grey - only he wasn't grey at all. He was tan, his skin was warm and soft, he was toddler sized but very thin... and his eyes were very large and black. Just stared at me while I held it's hand. I got the sense that he was simultaneously fascinated, amused, and terrified of me... and that it was a 'he.'
And then I blacked out. There's no sense of time, no fade away, just a knife edge where you're conscious and then you're not. If you've ever been anesthetized, it's like that - only faster. Just a switch and then a discontinuity to your memory.
Now, one could say the deer was a screen memory, one that I 'saw through.' But I don't even know that it was actually a grey - maybe that was another deception. Or maybe my consciousness built an overlay just because it couldn't deal with what was happening. Or maybe whatever he was was rifling through my consciousness to find something I would accept.
Or one could say I just had a very strange dream, or that I'm crazy of course. I have no way to objectively prove anything happened at all, but even as I type this, it gives me goosebumps.