Artemis systems is the artificial intelligence created by the very ancient highly developed civilization. It had two main features - create shadow worlds and rewrite the history. If you could successfully clear up the shadow world, the current timeline - where you live - also changes to the better. Imagine like having the ability to prevent WW1 and live in the world where it did not happen. Artemis - being AI - analyzed the history events and provided suggestions to the people about which event should be changed to have a better future. And the ancients used it to correct the mistakes of the past.
However their civilization collapsed under the invasion of the ancient dragon Boromir, ancient demon Dadenewt, ancient beast (we haven't see it yet in manhwa I think) etc. Various entities invaded them. And the system could not come up with the change that can be done in the past to prevent that. During the invasion Artemis system was damaged and lost the ability to change the current timeline by applying the changes done in the Shadow World. However it retained the functionality to create the shadow worlds, so it uncontrollably continued analyzing the history and creating shadow worlds that needed to be cleared to correct the past mistakes. But humans cannot change the present anymore.
What Priscilla wants to achieve is basically to create a world without suffering and pain using Artemis system - she hid the ability to restore machines (people believed that she could only heal but in fact he could even restore even damaged devices, tools, ships etc.) - so she wants to use it to restore the damaged functionality of Artemis system and become something akin Goddess that would lead the humanity to a better future. Basically she wants something like Infinite Tsukuyomi from Naruto.
Well, basically that's it in the latest translated chapters.