@diawolf123 As it turns out, there are plenty of options well within your budget that should run Sims 4 on ultra graphics settings. These two are the best examples, in terms of price and hardware, that I found in searching a few sites:
https://www.currys.co.uk/products/asus-rog-strix-g10ce-gaming-pc-intel-core-i5-gtx-1650-512-gb-ssd-10234732.html
https://www.amazon.co.uk/CyberpowerPC-Wyvern-1650-Gaming-PC/dp/B079YYRJD1
The graphics card in these is the same, and it should have no trouble with ultra settings even if Sims 4 gets somewhat more demanding in its last years of development. In terms of build quality, Asus does a better job in terms of build quality, as in, how the components are actually put together, and CyberpowerPC (a well-known brand here) uses higher-quality components, but they're relatively close on both metrics.
You could also get the next-faster graphics card instead. This is one example, basically the same computer as above except for the GPU upgrade and a different storage (solid state drive plus mechanical drive) combination:
https://www.amazon.co.uk/CyberpowerPC-Wyvern-1660Ti-Gaming-PC/dp/B079YWK948
Another option is to get a high-quality custom-built PC. It costs a little more, but it's still reasonable. As an example, I took this starting configuration:
https://www.pcspecialist.co.uk/view/Minecraft-Elite/
and upgraded to a Ryzen 5 5500, 16 GB (2x8) RAM, and a standard 512 GB SSD, and the price comes out to £795. (The other hardware is more than fine.) You could save a bit on the case if you want as well, but since that's somewhat of a personal decision, I didn't want to choose for you.
This one is even cheaper for similar hardware. I upgraded the processor (i5-10400F), graphics card (Asus 1650), and storage (500 GB Samsung Evo Plus, slightly cheaper and a lot better), and it came out to £745.
https://www.overclockers.co.uk/ocuk-gaming-kinetic-h5m-micro-atx-intel-h510-configurable-comet-lake-home-pc-fs-1f7-og.html
Between these two custom builders, I'd go with whichever one has overall better reviews in the last six months. They both have good reputations overall, but things can change quickly in this market. Both offer three-year warranties for labor as well.
In your position, I would personally go with a custom-built PC because the overall build quality will be higher, and the slight price premium would be worth it to me. But if you feel differently, the first options I listed should be perfectly fine as well.
As for monitors, there are far too many options to list, so here are three high-quality and relatively cheap models as examples:
https://www.amazon.co.uk/MONITOR-HP-1920x1080-ULTRASLIM-NEGRO/dp/B07PN63WQ8
https://www.amazon.co.uk/Asus-VZ239HE-23-Inch-Ultra-Slim-Monitor/dp/B073Q36551
https://www.amazon.co.uk/Acer-SB241Ybi-Monitor-Panel-FreeSync/dp/B09RQQYMHN
They all have IPS panels, the best in terms of color and viewing angle, and they're all the same size because at a 1920x1080 resolution, I personally wouldn't go above 24"—larger screens can look a bit grainy. You may disagree though, or want something a little different than these; if so, let me know what details you're looking for, and I'll do a more targeted search.
If you have more questions about any of this, please feel free to ask.
