@TrucyW There are lots of great gaming laptops available for Sims 3 in the 1100-1400€ price range, although not as many are light-colored. I did find a few quality options worth considering. All of the laptops I'm listing are capable of running all Sims 3 packs together, on mostly ultra graphics settings (there are a couple of settings that need to be turned down), with no issues other than how the game itself behaves. So the decision here is not about performance so much as the other details. The manufacturer doesn't matter as much either, aside from the overall quality, because they all use the same components from Intel, Nvidia, AMD, etc.
First, I want to say that this is the single-best laptop I found in terms of quality and longevity, but it may be too dark for your sibling:
https://www.mediaworld.it/it/product/_lenovo-legion-5-15arh7h-156-pollici-processore-amd-ryzentm-5-nvidia-geforce-rtx-3060-16-gb-ssd-512-gb-179518.html
Lenovo Legions are the highest-quality standard gaming laptops (as opposed to much more expensive premium products), and Lenovo has a reputation building laptops that last for a long time. As I said, there's never a guarantee, but relatively speaking, the products are more likely to still be in good working order than most others.
If the color isn't going to work, one of these is a good alternative:
https://www.amazon.it/Laptop-Lenovo-IdeaPad-Gaming-82SB00CPPB/dp/B0BZT7HQ58
https://www.dell.com/it-it/shop/notebook-dell/notebook-inspiron-14-plus/spd/inspiron-14-7430-laptop/cn74410
https://www.amazon.it/ASUS-K3605ZU-N1061W-alluminio-Antiglare-i7-12650H/dp/B0BRYDR8TH
https://www.eprice.it/Portatili-HP-Notebook-Victus-Gaming-15-fa1029nl-Monitor-15-6-pollici-Full-HD-Intel-Core-i7-i7-13700H-16-GB-DDR4-SDRAM-512-GB-SSD-NVIDIA-GeForce-RTX-4050-Wi-Fi-6-802-11ax-Windows-11-Home-Bianco-8Q2V7EA-ABZ/d-67582042
https://www.dell.com/it-it/shop/notebook-dell/nuovo-notebook-inspiron-16-plus/spd/inspiron-16-7640-laptop/cn76604sc
The RTX 4060 (last option) is faster than the 4050 (three and four above) and 3060 (Legion), which are faster than the 3050 (first two), but even the 3050 is more than capable of ultra settings. All of these have 16 GB RAM, which is very nice to have if not strictly necessary for Sims 3; and more than enough storage for the game and lots of extra saves. The reason I've listed some overpowered options is that there really aren't a lot of silver laptops, so this is about giving you some variety in the other details, for example screen size and weight.
One important detail here is that for the laptops with Intel processors, Sims 3 probably won't run out of the box without a workaround. I don't know for sure about all the models, but the i7-13700H is definitely affected. The AMD processors are not, but there are very few silver laptops with an AMD CPU and a good-enough graphics card, at least this generation. The workaround is to apply the patch described in the accepted solution of this thread:
https://answers.ea.com/t5/Technical-Issues-PC/Sims-3-won-t-open-Alder-Lake-Intel-12th-gen-CPU/td-p/11057820
It's a one-time patch, applied to TS3.exe (EA App install) or TS3W.exe (disc or Steam install), so this is not something your sibling would have to deal with long-term. But I do want to mention it since the problem would be immediate and unavoidable.
Framework laptops don't have their own graphics cards, at least not yet. I don't think you or your sibling wants to deal with a bulky add-in card, and the integrated graphics are somewhat iffy for Sims 3. If your sibling were willing to work through the issues playing on a borderline GPU, or your budget were more constrained, there are good-enough options, and some people playing on these integrated graphics chips report having few problems or none at all. But others have a lot of problems, and it sounds like you'd rather pay more to avoid this possibility. But let me know if that's not the case, and I'll find some good-quality laptops with high-end integrated graphics.
As for updates, there is always a chance of an update corrupting the operating system. A lot of the reasons for this come down to user error: not updating frequently enough, changing system settings they don't understand, downloading malware, etc. Some are not the user's fault, like a problem on the Microsoft end, and some are random. But as you know, avoiding updates entirely is not a good strategy.
The best ways to minimize the risks from updating are to update frequently, so the computer isn't missing a previous update that a new one expects; and to wait a week or so before major updates. Windows will let you choose when to install a new feature update, up to a point, and you can choose to install the newest Nvidia graphics driver or not, for a while at least. Most of the problems arise in the first few days after an update is released and are corrected quickly. You should never be forced to install an update as soon as it's available, and you can disable automatic updates wherever you find the option.
If there is a problem, what you can do, if you or someone else is available to help your sibling, is run a repair install of Windows. This does what it says: it repairs the Windows install itself, without deleting user data. You create a Windows installer, using Microsoft's own process, and let it overwrite any corruption; and it gives you the freshest version of Windows you can get without wiping the computer. It should only take 5-10 minutes on a fast system like the ones above. Here's how (option two is more thorough, but option one is a good place to start):
https://www.elevenforum.com/t/repair-install-windows-11-with-an-in-place-upgrade.418/
This doesn't fix absolutely everything, but it does address most problems, and it's easy once you've gone through the process for the first time.
If you have more questions, please feel free to ask.