@Sthenastia How many packs do you own? Certain packs do come with an additional world. I own all packs, so I have a lot of worlds (20 'home' worlds and 3 'destination' worlds). That's not to say that I wouldn't love a new 'Newcrest' type world added to basegame, as I do almost all of my building there, and many of my main Sims live in those homes. I would very much LOVE to have a new world like Newcrest added. 🙌
Personally, how I 'add new real-estate/story options' typically is I begin a new game save, or, for me, most of the time I save my current or desired game as 'Save As' and give it a new name. then I double check in the 'choose game save to open' screen to assure myself that this new game save is there AND that the previous game save is still there with everything intact (I even open the previous game save to confirm this, and I have an over abundance of caution when it comes to these things)... and THEN I enter the new game save I just made and go crazy with removing everything and everyone I can do with out in my new save.... but I also keep certain Sims, even if I evict them to open up real estate (and make sure the setting is not ticked to let the game auto-fill homes). This way I have the options of having whichever Sims I still want in the new world there (and with relationships intact).