@TrucyW I just wanted to reassure you that every laptop I listed was at the very least a good choice, even if some are better (in terms of hardware) than others. So whichever one you choose, for whatever reasons matter to you, should work great for Sims 3. I also completely understand being picky about the details, and that you or your sibling might find a problem with a laptop that I didn't see, like the number pad on the Legion.
For the IdeaPad, there are a few different subcategories: Gaming, Touch, regular. The Touch are the only models that have a rotating screen because they're supposed to be 2-in-1, as in, can be used as a tablet. The IdeaPad Gaming models don't have a touchscreen and therefore don't have a swivel screen either. You can sort of see it on the Amazon product page, but if you want to watch a video, be sure to look up "IdeaPad Gaming" and ignore any Touch models. The specific Amazon model is 15ARH7, which is this one:
https://psref.lenovo.com/Product/IdeaPad/IdeaPad_Gaming_3_15ARH7
Battery life is always going to be mediocre to bad on a gaming laptop. The powerful hardware uses a lot of energy, and batteries have to be under 100 watt-hours capacity to be allowed on planes. For comparsion, some laptop graphics cards use more than 100 watts when maxed out. Besides, playing games on battery is a bad idea because it hurts performance—the laptop will throttle to conserve battery, which won't work but will slow down the processor and graphics card. AMD processors do generally use less power than Intel ones, but you're only getting a small benefit most of the time.
I can't tell you what a keyboard will be like just from a product page, so you may want to take your sibling to a store to try out some display units. Even if that particular store doesn't have the exact laptop you want to order, a different configuration of the same overall model, for example a different IdeaPad Gaming, should have the same keyboard. This is to some extent a personal choice—some keyboards are clearly better than others, but there are very different styles of keys and switches even within one tier of quality.
For the other details:
- Extra ports are great but not essential since you can always buy a cheap adapter or hub. There's also a wide variety on gaming laptops.
- All gaming laptops are designed to make sure they can keep themselves cool even under heavy loads, including sufficient fans and vents. You can help with cooling by limiting in-game framerates in Sims 3, and you should do this anyway (and I can help once you have the laptop in front of you); the game won't max out the hardware either.
- Most but not all gaming laptops allow for RAM upgrades. The first one below cannot be upgraded, the second one has one free slot for an upgrade, and the third should have two slots but I can't find the exact model. The storage is pretty much always upgradable.
- These laptops should have ethernet ports, but if one doesn't, you can get a USB to ethernet adapter for maybe 10€.
- These laptops are all the standard 15-16", as you said.
I went through the sites you listed, some again, and I found a few options that weren't in my previous post. The HP site didn't have anything worth mentioning, and neither did the Dell other than the base model of the one you linked. The only laptops on the Lenovo site with gaming hardware and no number pad have 14" screens. I'll list everything else below just for simplicity.
These two are basically the same, other than the processor (AMD in the first, Intel in the second) and the faster RTX 4050 in the second. They both have a small number pad, and I don't know whether that's a problem too or the issue is the larger one the Legion has:
https://www.unieuro.it/online/Notebook/M6500QC-HN063W-pidASUM6500QCHN063W
This one is too expensive for its hardware (still overkill for Sims 3; it's just that the price is high for the components), but since it's silver and has no number pad, it's worth mentioning:
https://www.trony.it/online/informatica/computer-portatili/notebook/acer-notebook-gaming-predator-triton-neo-16-ptn16-51-50ft-16-pollici-silver_sku-2240001254
Predator is Acer's high-end gaming category, and Triton is the premium model within that group. So while I wouldn't recommend an Acer Nitro or standard Predator, this one should be great. But I'd still go with a Dell or HP at the same price.
For the Dell you linked, the base model with 16 GB RAM is more than fine. Sims 3 can only use a little less than 4 GB, Windows uses 2-3 GB, and Dell's bloatware can eat another 4-5, but that's still not anywhere close to maxing out the memory. This is a new model, and documentation online is scarce, but the Dell manual shows two standalone RAM modules, meaning the memory is upgradable:
https://www.dell.com/support/manuals/en-us/inspiron-16-7640-laptop/inspiron_16_plus_7640_om_4060_4050/major-components-of-inspiron-16-plus-7640?guid=guid-edfdb749-d5e5-4767-8ee1-bcb485908416&lang=en-us
You can of course ask Dell itself if you want to be sure.
The other components of this computer are overkill for Sims 3, not that that's a bad thing. As mentioned, an RTX 3050 is more than capable of ultra graphics settings, and so is any processor paired with it. Don't worry about the speed of the RAM; you'd have to run a formal benchmark to notice any difference at all, at least at these speeds. And a 16" screen with a high resolution, as this one has, is a very nice quality-of-life improvement even if it's not necessary.
Point is, the base model is far more power than you need, but upgrade to 32 GB 5.600 MT/s if you really want to.
It's fine if you have more questions, about these laptops or in general.