Lore Explanations for an Arknight newbie.

Im sure this has been asked for and mentioned a million times by now, so first my apologies for that.

Im looking for relevant lore to endfield, ive tried about a dozen youtube lore videos at this point, and while i get the lore is very deep, im looking for concise information regarding how endfield came to be specifically. A lot of the videos ramble on about somewhat irrelevant things to the new game, for example the various city states on terra, whereas im looking for specific information on how that transitioned into this new world we find ourselves in.

Im sure there's a lot of lore nerds in here who'd be willing to offer up info, and i welcome that as im a 40k lore nerd myself. If not, i'd appreciate any youtube links you guys can offer to help me make sense of the prologue of endfield.

Having completed the prologue of endfield pretty much nothing is making sense to me at this point, and im not sure if thats intentional or im supposed to have some background lore as to why the world is frozen, the grim reaper caused a triangle in the sky to explode, and why a countdown to 0 ends reality.

Im loving the gameplay and characters so far, but im just a bit lost in this setting at this point. I'd love to understand more so i can be more immersed.