@LittleMissAly There are unfortunately not a lot of good gaming PCs available right now. The market hasn't calmed down yet, and manufacturers are transitioning between the older 16- and 20-series graphics cards and the newer and more expensive 30-series. You can still do better than a 1030 though. For example:
https://www.amazon.com/SkyTech-Blaze-Gaming-Computer-Desktop/dp/B08VYDFMS8
This one can run Sims 4 on ultra settings now, and it has room for improvements in the future if you need them: the processor and graphics card could be upgraded, and you could add more RAM.
If you want to keep the price a bit lower, the above applies to this one too, except the 1050 ti is a little slower than the 1650: you should still be able to use ultra graphics settings, but maybe only barely. I wouldn't say it's a better deal overall—the faster card is worth the extra $50—but if you'd upgrade the card regardless, you'd end up saving money by initiall getting a cheaper one. The processor in this model is better than in the one above, but both are fine for Sims 4.
https://www.bhphotovideo.com/c/product/1642272-REG/ibuypower_slatemr149i_computer.html
If you're not in a hurry, an alternative option is to configure this model to your liking. It starts at $650.
https://www.hp.com/us-en/shop/pdp/hp-pavilion-gaming-desktop-tg01-2170m-pc-3v2z3av-1
I would definitely upgrade the SSD to 500 GB (+$40) and the graphics card to either a 1650 Super (+$20 and a few percentage points faster than a regular 1650) or a 1660 Super (+$90, much faster than the 1650s). I wouldn't pay to upgrade the RAM; save some money and do it yourself if necessary. The build quality of this computer isn't as good as the others, but it's certainly not bad. The real advantage though is you'd get a faster graphics card for your money. This is about your priorities though: absolute performance vs. build quality.
As for monitors, it does sound like you'd benefit from a high-res screen, specifically 2560x1440. Many people are fine with 1080p, but the higher resolutions do make a difference to plenty of players, especially those who are attuned to visuals as well. Choosing a monitor is about personal taste as much as anything else, but the important details are the resolution, the panel type, and of course the physical size on your desk. Among panels, IPS is the highest quality in terms of color vividness and range, at least until you get into much more expensive options.
Since I can't tell you what you like, I'll list a few examples of good 1440p IPS monitors so you can get an idea of what's out there. They're not cheap, but they do start at $100 less than the one you linked.
https://www.amazon.com/Lenovo-L24q-30-23-8-inch-Widescreen-65FBGCC1US/dp/B089FJS412
https://www.amazon.com/LG-24QP500-B-FreeSync-Virtually-Borderless/dp/B08YJWYMD5
https://www.amazon.com/Acer-KA272U-biipx-Zero-Frame-Technology/dp/B08JQSBNYH
https://www.bestbuy.com/site/6453642.p?skuId=6453642
Quality 1080p IPS monitors are cheaper, and if you get a smaller one, you might be fine at the lower resolution. I wouldn't go higher than 24" though.
https://www.amazon.com/ASUS-VL249HE-Adaptive-Sync-Frameless-Mountable/dp/B08LCPNPNG
https://www.bestbuy.com/site/6454576.p?skuId=6454576
https://www.amazon.com/SAMSUNG-Computer-Border-Less-FreeSync-LS24R350FZNXZA/dp/B091BCRJR7
The FreeSync feature doesn't really matter here: FreeSync is an AMD feature, and only some of the monitors will also work with Nvidia's G-sync. Besides, you can achieve the same effect with software.
If you're not sure what you want out of a monitor, the best thing to do is to go to a physical store, e.g. Best Buy, where a number of monitors are on display. You'd get a sense of how each resolution looks at different sizes as well as which manufacturers' panels you like. Even if the store doesn't have the models you're considering, you'd still have a better idea of what to look for rather than relying on Amazon reviews.
If you have more questions, please feel free to ask.