I recently observed on my game that if I fill a lot of households on Other Households tab with enough elders, YA, teens and children, the game will not generate new random households for a while.
I guess it works like: Lounges, e.g., usually are visited by elder Sims, so you need to have enough elders on Other Households bin to fill this lot with some of them, have some elders walking by the surrounding area and also a couple of them to refill the lot when the first ones go out. Bars tends to attract YA/adult Sims while parks will attract teens and children. You can apply this logic on all of those lots.
Lately I have been playing with only base game and Parenthood and I found out that if I fill the Other Households bin with the 2014 and 2019 premades Sims from Maxis profile plus promotional Sims from Parenthood, the game doesn't need to create new households except to fill jobs as caterer, mixologist, pianists etc.