I draw since I was a kid. I had very little formal training. I finished 3 semesters of an advertising school around 2010. It included live drawing classes but we received very little instructions. Still, it managed to improve my drawing a lot - mainly thanks to having a book titled Fundamentals of Drawing by Barrington Barber.
Between 2010 and 2014 I was wasting my time and money trying to get into IT/vaguely pursuing a my dream of becoming a game developer.
Due to much values orientated personality and not deriving pleasure from bending hardware/software to my will and general lack of interest in new technologies, I haven't got deep enough in into it to make it a viable career or at least allow me to make a game.
So, I'm back to taking drawing seriously.
I think humanity can't reinvent because it was AIs doing the inventing, not humans. And AIs are gone. Even other empires depend on salvaged STC technology.
Also, the success of the Imperium in Great Crusade demonstrates that it was the greatest power and others simply couldn't compete with it.
Then there's the next layer of the tragedy that the Great Crusade was a necessity as when the warp storms calmed all human civilisations that survived in isolation were ripe for picking for stuff like Ork waaghs. It was a brief period when humanity had two possibilities - reunification or extinction.
Like ultimately, there was only one strong source of human regrowth which was the Imperium with its Emperor, Primarchs and Space Marine legions.
The biggest problem was that the Imperium was humanity's best shot.
Perhaps the real problem is that humanity haven't went extinct in a world no longer worth living in.
It was a short story.
40k has started out as a mix of tragedy, satire and pop-culture references, pretty much like Fallout 1. Rick Priestley has quickly lost creative control of it and it became much more literally medieval with lots of over the top stuff that at the same time takes itself completely seriously.
Like pretty much the whole set up is to make humanity miserable even without the Imperium. Like loss of AI, use of servitors, hive cities, travel through hell, emergence of psykers and need to suppress them, danger of warp creature possessions and all that stuff that makes humanity miserable all predate the Imperium.
This makes the whole story tragic because no matter what humanity does, it's screwed and the way the Imperium lives is pretty much a necessity.
Basing on the description Sisters of Battle were special religious police, not female equivalent of Space Marines. They were probably also more powerful than Space Marines since they were just enchanced thugs and Sisters of Battle seemed to be all special characters like Custodes. Like even all of their models had power swords.