ArilyBoo I'm not understanding either, and I don't know why this would be. In past years, I remember that Sims 3 wouldn't always respect CP settings on a laptop with dual graphics because the iGPU's driver settings were winning out, so to speak, but that hasn't been a problem in a while and I don't even know whether you have a laptop. I only have TS2 installed on a laptop with AMD graphics at the moment, and while could test on an Nvidia desktop, that's not relevant if the issue is dual graphics.
Do you own the Sims 1 legacy version, and does the CP's fps limit work there? I don't remember seeing any reports of runaway framerates in that game, but I also don't remember how to check (other than with the Nvidia overlay or another outside app). That game isn't necessarily a valid comparison either, as it was redone to use Vulkan, but it would be interesting to know.