Actual Maximum Sim Count in a game?

Hello, I was curious about the same thing some years ago when I had over 800 sims, I was scared that when I pass 1000 my game will crash or something, but to my surprise it still works really smoothly, when I had around 900 sims the births started to lag pretty badly, but then eventually as it was closer to 1000 the lag just dissapeard. Maybe my save is evolving to fit more sims, who knows. Anyways, I have now 1009 sims in "my families", (I have ~8 year old save where I control the whole city so its justified) and for now I see no red flags, but I'm also pretty scared if it's going to reach it's limits one day. And secondly, I've noticed after passing 1000 far less NPC's spawn. I play a tour gameplay, so after every family I deliete unnecessary townies, and I've noticed that now almost none spawn now which is honestly pretty cool. Of course they still appear but I'm curious how it's going to affect my game.  I have exactly 1011 sims counting "other families".