Are they?

Yes.

"All Men Must Die" doesn't mean that the FM are trying to bring about the apocalypse. That's just a statement of fact: all men are mortal, therefore all men must die by definition. It's the "All Men Must Serve" that's much more interesting. What does that mean?

I didn't say it necesarily did. I'm saying that the only way I could see them working with Euron is if they are trying to bring about the apocalypse.

Which gives a LOT more meaning to the FM ideology and practices if this is the case. The FM aren't just killing people, they're knowingly changing the nature of reality by ending someone in a different time, place, and manner than would otherwise have occurred.

Dude. I have said this to only a few people before, and now I'm going to say it to you.

I think you should scrap every single theory you have, because I think you're completely delusional about the story.

You're missing the point: it isn't that the FM have their "own" collective consciousness, but that they acknowledge that all collective consciousnesses are just fragments of the same process. All I've done here is insert "collective consciousness" into their known philosophy in place of "gods."

No they haven't.

What if they have been, though? What if this is what they did in Valyria? Amalgamated the "Thousand Gods of Valyria" into a single, unified "deity".

There is no evidence this happened.

No, the reason I'm more interested in the lore is that I'm more interested in the lore. Stories are stories. Lore is what makes fantasy different from other genres. It's what draws me into "constructed world" fiction in the first place. It can be used to convey themes and ask question that story and character alone often can't. To make us question the nature of our own reality.

But it's totally shattering any understanding you could have of the story.