Lyana2 What do you think of this computer?
https://www.bestbuy.com/site/ibuypower-scale-gaming-desktop-valorant-vcta-amd-ryzen-7-7700-32gb-memory-nvidia-geforce-rtx-4060-ti-8gb-1tb-ssd-black/6576678.p?skuId=6576678
This is significant overkill for Sims 4, but that's pretty reasonable given its price. It's the cheapest system I'm seeing with an RTX 4060 ti, by about $100, and nothing I found under $1,200 is any better. It's also only about $100 more than computers with a 4060 non-ti, which would be something of a downgrade if still overkill. The RGB fans don't look great to me, but their colors should be adjustable.
This one has a 4060 ti as well and a processor that's not quite as fast but still more than good enough for whatever you want to do with it. The system does only have 16 GB RAM, but you could upgrade should that ever become an issue. More relevantly, the memory is slower (DDR4 vs. DDR5), and although that won't make any obvious difference in Sims 4, it might affect professional-level workloads such as compiling code or encoding videos if you're interested in that kind of thing.
https://www.amazon.com/Thermaltake-i5-13400F-ToughRam-GeForce%C2%AE-S2QT-B66R-46T-LCS/dp/B0CR56R8KG
The next-faster graphics cards currently available are the RTX 4070 and AMD RX 7800 XT; systems with these start around $1,500. The extra power would be completely lost on Sims 4, so the only reason to consider it would be fore other games. Keep in mind that you can always upgrade the GPU in the future if something new and exciting comes out that your current card can't quite run the way you like. Still, let me know if you'd be interested in some of these options.
If you don't like the two I've linked above, please describe why. There are lots of good options with similar specs, just not as cheap, so I could find something to fit pretty much any preferences.
Many desktops come with cheap and low-quality peripherals thrown in for free. I wouldn't recommend using the included mouse and keyboard for long, but testing them would at least give you an idea of what to look for when you buy a better version. Quality mice (e.g. anything Logitech) are cheap, good keyboards less so, but then you don't necessarily need a high-quality keyboard, just something that feels good under your fingertips. I'd suggest visiting a Best Buy and putting your hands on the demo models to get a sense of what you like.
For the monitor, your budget and the hardware you're looking for would handle a high-resolution, high-refresh-rate panel without trouble, at least when running Sims 4. The important details are resolution (2560x1440 is the sweet spot), refresh rate (100 Hz at least; higher means smoother up to a point), panel type (IPS is the highest quality; don't compromise on this), and brightness (300 nits minimum). Any of these would work:
https://www.bestbuy.com/site/msi-pro-mp275q-27-qhd-100hz-1ms-adaptive-sync-monitor-with-built-in-speaker-displayport-hdmi--black/6583175.p?skuId=6583175
https://www.bestbuy.com/site/msi-mag-275qf-27-qhd-rapid-ips-180hz-0-5ms-adaptive-sync-gaming-monitor-with-hdrdisplayporthdmi-metallic-black/6585692.p?skuId=6585692
https://www.newegg.com/msi-pro-mp273qp-e2-27-qhd/p/N82E16824475393
https://www.newegg.com/gigabyte-g27q-27-qhd-144-hz-ips-black/p/N82E16824012015
The first two have a 300-nit brightness, which is good enough; if you want something brighter, the third and fourth are 400 and 350 nits, respectively. You'd likely notice the difference between 100 Hz and 144 or higher, but it's somewhat subtle, not like the difference between 60 or 75 and 100. You could also test the monitors at a Best Buy in person to get an idea of how different refresh rates feel.
Here again, there are lots of options that are close in price to these, so if none of them is exactly what you're looking for, just let me know why, and I can do another search.
If you have more questions about any of these or in general, please feel free to keep asking.