How to stop the game from changing families relationships etc when I don't play?

Hello everyone.

First of all sorry for my grammar / english mistakes as I'm not a native english speaker;

I've been playing the Sims since the Sims 1 when I was a kid. I had all of them : the Sims 1 on PC and Game Cube, the Sims 2 on PS2, the Sims 3 on Macbook and now the Sims 4 on an iMac. I always considered myself a big fan of the game and I spent countless hours of playing it. The only thing that always bothered me is the fact that the game keep playing with families I don't use "behind my back". I hope you understand what I mean... My goal, never achieved, was always to create a full world, a full city, all by my hands, and not having random sims appearing, dying, having babies etc. I thought I could achieved that with the Sims 4 with the help of mods and cheating codes but it seems to be impossible as the game keep changing relationship ans stuff with families I don't play with... 

For context : I play the Sims 4 on an iMac. I have almost all the extension packs and so almost every worlds available. I used "testingcheats true" with "cas.fulleditmode" and the mod "MC command" to modify relationships and careers. I modify all the options of the game so that the sims are not able to get old (even Sims I don't play with) and canceled the stories options so the Sims aren't supposed to have big changes in their life when I don't play with them. By clicking on the "heart" symbol I put all the families of my worlds on "My Sims" category and not on "Others Sims". I get that the game will still gonna create random new Sims anyway and I can't do anything about it. The explanation I get throughout the years is that there is a need for news Sims to fill some jobs (cashiers, vets, nanny...) so it's not possible to only have in the game the Sims I created or edited unfortunately. 

A few weeks ago I started to edit all the families of all the worlds I have. I redid the houses, changed the names of the Sims already created by the game for names that I like more, changed the outfit... With the help of the mod I create my owns stories with families, adding relationships (brothers, daughters...) creating like a lot of interesting stories. For exemple, in the "Oasis Spring" world, I took an already existing family and made them aliens with blue skin and space related jobs, redoing their house with an astronomical/robot theme. I edited an other alien Sims that was a random blond hair guy in the Japanese/mont Ito world and made it a brother of the father in Oasis Spring. An other exemple : I edited a random girl in the pacific land and made it an scottish girl with a scottish name and edited a old lady in Willow Creek and modify the parental link so she became her mother, even thought they don't live together. I spent hours and hours rebuilding 10 worlds (!!), redoing all the Sims that were already there, creating stories, houses, lives, relationships links between them... I thought I selected all the options of the gameplay for preventing them to move and evolve too much when I don't play with them. I, of course, don't mind small changes but I was worried of some of them dying, disparearing, changing houses, changing names, having too much babies... I was almost done with my work of editing my entire game when I notice that they were already a lot of changes... For exemple an Indian mother of triplets divorced and is now living with a Chinese Sims living in a total different world, even thought I put this two Sims in the "my sims" category and that I disabled the new program "stories" so that my Sims are not supposed to have big changes in their life, or that's what I thought. That's not the story I wanted for these Sims. An other and worst exemple : the game add families link between some of my Sims ! An old Japanese guy is now the father of the dad of the Alien family. The French sisters are now sisters with 3 random others Sims I edited. Of course I can modify that, but what a waste of time !

I hope you get what my problem is. Is there a way from stopping the game from modifying links between the sims (making random Sims brothers and sisters overnight...) and stop having too much gameplay changes (divorces, moving houses, quitting job...) ? I get that some people love that the Sims we don't use are living their life anyway, it give realism and mouvements to the game. But adding family links between them doesn't make any sense... The Sims would be so perfect for me if we can prevent it from doing that. 

Thank you so much for reading me,

Long live the Sims anyway,

Isabelle