I think it's hard to answer this question with specifics, so I'll just share my experience. I'm not sure if it'll be helpful, but maybe ... 😄
My computer stats: 13th gen i9, 64 GB RAM, RTX 4090 (24 GB graphics card) - it's 1.5 years old
I play on the highest settings, use ReShade, have almost 7,000 CC/mod files installed (almost 30 GB), use MCCC to up the lot limit to about 50 Sims (full disclosure: I can't remember if I made this lower because sometimes small lots actually get too crowded and there are no seats or my Sims cannot use objects I want them to use because they're already in use). I have every EP, GP, and SP except Werewolves and Batuu. I have several kits too. I have basically no lag (cooking menu takes a second or so to pop up probably because I have almost 200 food-related mods installed - there's a noticeable pause, but it's very very short). The game loads in about a min. The main lot I play on is a detailed 64x64 lot valued at $1.1M simoleons. My save file is under 40MB, though. I think FPS is about 150 on a widescreen monitor, but I don't pay attention to that so I could be wrong. I constantly run other applications on a second monitor and I generally don't use more than 50% of my CPU or GPU power with everything going.
I didn't have issues on my old computer, which is 6 years old either. I don't remember the CPU, but 32 GB RAM, RTX 2080. I did basically the same things.
BUT there IS NOT any computer that can guarantee this game runs well under stress (huge save file, lots of sims, detailed lot). A lot of people are running into save corruption issues, which seem to be exacerbated by customizing lots, Sims, etc.
Back of main lot for reference (originally the park in San Myshuno):
Community Manager
