I'm going to give a piece of advice that most people will disagree with -- if you have the budget for it, get a gaming laptop.
Here's my reasoning:
Video cards are ridiculous right now thanks to crypto currency. They have been for years, mind you, but right now it's impossible to get a decent video card at a reasonable price. Even prebuilt desktops are reflecting this. And it's not getting any better any time soon. Due to the prior year's events, material shortages may make things worse.
This assumes you're getting a system with a discrete (non-integrated) graphics card. Another option would be to buy a desktop with the most powerful CPU you can afford and use the integrated graphics and worry about getting a graphics card later.
I think most importantly, laptop or desktop, you want at bare minimum an SSD (solid state disk) as opposed to an HDD. Even better if you can get an m2 NVMe. Many prebuilt systems for whatever reason toss a HDD in, even if it's just a second drive. They are slow and clunky and more prone to hardware failure.
I suppose this is a non-answer. Easy answer is look at the recommended specs for the Sims 4, and get better than that -- as much as your budget will allow.
Edit: Laptops usually use a smaller, less powerful, made-for-laptops graphics card. These are not being used by cryptocurrency miners so you have a better chance of getting more bang for your buck. A quick google search showed me you can get a laptop with a 2060rtx, which is the last generation midrange card and an i7 CPU for $1100, or the desktop 2060 rtx only (nothing else, just the card) for $800-900. Unfortunately, even the lower range cards desktop version are going up in price. I looked up a 1650 gtx, which is a budget gaming card, and the desktop version is going for between $400 - $500 while you can get a laptop with that card for just a couple hundred more.