How does the RNG is ck3 function?

games all over have different ways of producing rng, for example, there is a title in the xcom series i have heard calculates the dice rolls for cover and shooting chances at the loading of a level and the percentage displayed is only the chance it had in the dice roll at the beginning, and that if you don't load a save from before entering a map that the 67% chance to hit on an angle that fails will continue to fail, some are a legitimate dice roll where as soon as who engage with the action it will produce a number and depending on said number compared to a success chance you win/lose and it is genuinely random every time.

i am a shameless save-scummer, i don't like being beaten down in a single player experience when i'm trying to make pan-irishism across europe for shits and giggles, but i've noticed that very often even after reloads certain events will appear to always happen. for example, a plague hit ireland, i did the things, locked down the capital, secluded us, etc. my wife got sick, went with the soft approach and died, my heir got sick, went with the hard approach and he died, reloaded the save, changed the approaches for both, they both got sick and died in the same order, reloaded 4 times, going with hard approach on the first two reloads for both and then soft for both on the next, in all for saves the wife got sick, the kid got sick, the wife died and then the kid died, the kid died at 14 years of age across 10 saves regardless of capital status, approach to disease, etc.

i reloaded an even older save, changed some stuff and the plague didn't occur, fast forward 7 years and i unfurl a murder scheme on a powerful vassal, on phase 2 my daughter dies in childbirth at 27, ending my alliance with france and then my plan is discovered, reload the save, phase 2 rolls around, my daughter dies at 27 in childbirth and my alliance with france is ended, my plan is discovered and falls through, reload save, use new people in the scheme, daughter dies at 27 in childbirth french alliance ends, plan discovered.

I am really curious how the rng in this game functions, i believe you guys know as this community seems to know this game like the back of it's hand, what is the RNG system and how do i work around it?