The MC's system is actually an inheritance artifact that's disguising itself as a system so as to more easily interact with its host, who comes from a modern world and was initially a fish out of water in the cultivation based world.
Apparently, the founding emperor of the previous dynasty was a visitor from the real world too. In his fake imperial tomb, he left a note that has the location of the real tomb written down in English, which only the MC could read. Then in the real tomb, they find books and drafts of modern weaponry, as well as early experiments into explosives and guns. Though, the story is realistic in that the empire isn't advanced enough to immediately start mass producing guns yet, so only one gun show up near the end of the story.
From the chapter mid-thousands, early two-thousands, more an more of the narrative will be spent on the MC's adventures in the world of the system and system-users, as she tries to advance herself, build her own world, and endures various setbacks. These parts are a bit YMMV. I found them interesting at first because the MC starts interacting with other system-users and sometimes go on group missions to various worlds. But later on, I feel like the MC seems to get dumber every time she's outside of the mission worlds, like she's just asking to get herself killed, and often times acting just like the idiots that she looks down on and acts against during her missions.
That said, there's still a lot of interesting world building, and some very cool mission world arcs that I really liked. And it did hold my attention all the way to ch2971 (which is the current chapter as the story is a WIP). So I'm giving this novel an overall 4.
My favorite arcs are:
The second one as the emperor's sister, which was able to capture my attention for the rest of the novel, and also introduced the interesting emperor guy who actually pops up again later, more than once.
"That Phoenix Guy" arc, where the unfaithful/murderous husband the MC puts into jail later commits suicide and then becomes a fellow system-user, much to MC's (later justified) paranoia.
"The Merchant's Daughter" arc, where due to an incident in the previous mission, MC is directly dropped into a mission without any system help, which includes getting background info on who she is and what her goal is supposed to be. She has to figure it all out and deal with the unknown danger with only what skills she's retained so far.
"Demon Sect Lady" arc, where MC kills off the original ML of the world right after she arrives, and spends the rest of the arc trolling the entire rest of the setting.
That time the MC transmigrates in as the male emperor (not even the first time she's cast into a male body) and has to deal with a harem full of transmigrators, wild system-users, rebirths, etc.
The war arc that takes place in the system-level place between-worlds, where MC and a bunch of other high level mission takers get basically drafted to defend their corner of the multiverse against... bugs?rats? It's the first time we get to see a lot of the other major departments of the overreaching organization that manages the system-users.