plasticbatcat Sorry that no one responded to your earlier than this. I've been away from the forums for a while and am only now getting back in.
If you're still shopping, are you looking for a new prebuilt PC or to upgrade your current system? Prebuilds make this question easier because all the other components are sufficient to support the graphics card, which is always the most expensive hardware relative to performance. So whatever GPU the system has, the CPU will more than keep up, and it'll have enough RAM and certainly enough storage for Sims 4.
If you want to upgrade your current system, that's a different matter, since the motherboard will only support certain generations of processor. In that case, please list your current CPU, GPU, RAM, and storage (size and type of drives) so I can get an idea of what you're working with.
In either case, please list your budget and country, and I can give you an idea of what to look for.