@xxlMarii My advice for Sims 3 is to get the fastest integrated graphics chip you can for your budget. A dedicated graphics card would be better, but that's not available in laptops for $400 or less. And I've heard from a few players that a fast iGPU can run Sims 3 on high-ultra graphics settings most of the time. That doesn't mean that any laptop is fine, only that you don't need a gaming system to have a good-enough experience.
This is the best new option I'm seeing for $400 or less, at least where Sims 3 is concerned. It also has 16 GB RAM, and 512 GB storage, both of which are convenient if not essential. The biggest downside is that the screen is not that great. It would probably be okay in a darkened room, but playing with the lights on might not look good.
https://www.bestbuy.com/site/asus-vivobook-15-laptop-amd-ryzen-7-5800h-with-16gb-ram-512gb-ssd-quiet-blue/6597355.p?skuId=6597355
This one's screen is better, and it's about the same speed, maybe a bit faster in Sims 3 (reports are inconclusive). It has the same 16 GB/512 GB configuration:
https://www.dell.com/en-us/shop/dell-laptops/inspiron-15-laptop/spd/inspiron-15-3520-laptop/nn3520gsbbs?ref=variantstack
If you're comfortable with a refurbished model from Best Buy, this one has the same graphics chip as the Dell and a brighter, prettier screen than either of the above. While 256 GB RAM isn't a lot, it's more than enough for Sims 2 and 3 if you pay attention and offload extraneous files (extra saves, music or movies, etc.) to an external drive.
https://www.bestbuy.com/site/lenovo-thinkpad-t14-gen-2-14-intel-core-i5-1145g7-16gb-ram-256gb-ssd-windows-10-pro-refurbished-black/6599000.p?skuId=6599000
If none of these is exactly what you want, let me know how, and I'll look for other options. I do see some with only 8 GB RAM, which is enough for either game as long as you don't multitask too much, but it's better, all else being equal, to get 16 GB. Still, if these options aren't good for you, a laptop with 8 GB memory is a viable alternative.