@Braxien In addition to @CGrant56's mention that there is at least one mod that will help you adjust the invasions settings, you can also add a GTW satellite (the one from the Scientist career) to a home in each neighborhood. Then through an active Sim on that lot, in each case activate the setting that stops alien invasions for the neighborhood.
If you don't have a Sim capable of creating these you can find the satellites in Hidden Objects (open the cheats panel > enter bb.showhiddenobjects > go to electronics > misc (it's called "Satellite Dish"). I added one to a room then saved the room to the gallery, so you should be able to download this to your library then place it as many times in your game as you want (they cost $500 each): https://www.ea.com/games/the-sims/the-sims-4/pc/gallery/04264AC6BF0911EA87670EF682150483
Place the room on each of these lots and grab the satellite in build mode and stick it on the roof, then in live mode have a sim activate the settings you want. I just added a room with a satellite in the gallery if you want to just use that one.