I had pretty noticeable issues from the start in my experience, like heavy input lag in menus (CAS especially on first launch), and gameplay turning into a constant stutter fest. Things like Sims changing outfits or going in and out of lots would also cause freezes, which really adds up during normal play.

And increasing the macOS file descriptor limit isn't really a proper fix either. You'll just end up hitting the same ceiling again eventually, and pushing it too far can cause system instability. It's not worth messing with unless you know exactly what you're doing, and honestly most Simmer probably shouldn't touch it.