@DenisevdWoude92 G-sync is Nvidia's proprietary technology. FreeSync was created by AMD and does the same thing, for practical purposes, but it works with any graphics card. You don't actually need either one. Adaptive sync is a vertical sync setting within the Nvidia Control Panel; I'm not sure whether AMD GPU drivers have a similar feature.
All of these technologies attempt to remove the possibility of screen tearing due to the monitor displaying parts of two different frames at the same time, usually the current one and the previous one. This can happen because as the monitor refreshes, it loads the most current data available at that exact moment, and not all portions of the screen refresh at exactly the same time. So if a new frame comes in from the GPU in the middle of the refresh, the already-refreshed pixels will be showing the old frame, and the ones still refreshing will show the new frame.
Imagine you're moving the camera around, and the top half of your monitor displays what you were looking at 10 milliseconds ago while the bottom displays what you were looking at 5 ms ago. Now imagine your game looks just a tiny bit broken like that all the time, except when you're not moving the camera. It's not pleasant.
G-sync and FreeSync allow the monitor to wait until it receives the entire frame from the GPU to display it. The monitor also has a totally flexible refresh rate rather than a few presets, e.g. 30, 60, 100, and 144 Hz on a 144 Hz monitor. So if the GPU is providing 53 frames per second, the monitor can display each of those 53 frames right as they come in, with an effective refresh rate of 53 Hz, rather than refreshing at a constant rate and trying to fit the frames into that rhythm.
This is great for fast-paced games where you want the data to be as fresh as possible, for example competitive shooters, but matters much less for Sims games. So while it's a nice feature to have, it's not worth spending a lot of extra money. You can avoid screen tearing with only a bit more delay in the frames appearing by applying vertical sync, or adaptive sync if it works better, alone or in combination with an fps cap.
If you like AOC monitors, this one would work well. It's an IPS panel with good-enough brightness and a 165 Hz refresh rate, which is more than you'll get in Sims 4 anyway. (That will be less about the graphics card being maxed out than the game engine being what it is, but either way, no point in paying for a higher refresh rate than you can use.)
https://www.alternate.nl/AOC/24G2SPAE-BK-23-8-inch-gaming-monitor/html/product/1862248
This is brighter than the LG monitors I linked before, and equal in theory to the first one you linked, but as mentioned, IPS has better color range than VA, so the effect is not equal. In a dark room, the dimmer screens would be fine, but if you play with the lights on or sun coming through a window, you'll probably want a brighter screen.
Another helper mentioned to me that iiyama is a Japanese brand with very good but not top-quality products. I hadn't heard of the company and would still do some reading if I were considering buying one of its monitors myself, but let me know if you'd like me to look at these options as well.
Please don't apologize for asking so many questions. I answer here because I enjoy it, both helping players pick out the right system for them and talking about hardware in general. And this is a significant purchase for most people, so it's important to provide the best information I reasonably can.