[SPOILER CH. 6] What happened during Chapter 6?

[Vaibryn]

Hey people, I've just recently finished Chapter 6 and it left me really confused, so I'm tryna reach some fellow players who maybe understood it a bit better. (Also I really can't find any Wiki or similar that explains the Chapters. The game is criminally underrated)

From the very part on where Natsume got the gun from the mysterious person behind the door, I feel like the story lost me a huge bit in understanding.
So I suppose the gun was left for Natsume so he could kill Mamiya?
But what the hell was that interaction with Mamiya just afterwards?

In case some of this stuff is revealed in later chapters, please tell me instead of spoiling me. xD

There was 3 things that really confused me:
-1: First off, Mamiya constantly telling Natsume that they are the same and Natsume being thrown into these spiraling thoughts about the deaths of his friend. What does that mean and why was Natsume so extremely shocked about this revelation? Was it simply put, that Mamiya and Natsume are both manipulating the story for their own egoistical goals, which makes them no better than one another? Also Mamiya hinting at something in the same scene, that Natsume will only bring his friends happiness as long as he follows them as a spectator. This + the hint that the Trichiliocosm is somewhat connected to this library - does that mean his friends will end up there anyways?

-2: Mentioned just earlier - but did they suggest that the Trichiliocosm is where the Spectators reside? When Mamiya told Natsume what the Trichiliocosm is he just mentioned "The Library" in a short sentence and that really threw me off. Or what exactly is the connection between those two places?

-3: What's with Natsume and the extreme bleeding? Like it already happened before when some invisible forced ripped his skin open, but in this cutscene the flashback left his character picture completely covered in blood. Why? Did Mamiya turn into Togo Inumaki from Jujutsu Kaisen and physically hurt him with words?
Or was this just to visually show how deep the flashbacks hurt him?

So yeah, sorry for the wall of text, but this Chapter has been really eating away at my mind. I'm not sure if some of these might be translation errors, because my english usually isn't bad at all. Also, if you guys have some resources about the game (like a properly maintained wiki) feel free to drop me a link!
I've been loving the game so much, since I've started it and I know I'll 100% get the DLC too

Thanks guys!

[violet]

all of this gets answered either in DF or DDD so, keep an eye out
there's a wiki but it's still in work https://mamiyawiki.com/index.php/Main_Page