@Eira2011 It sounds like your first priority is 16 GB RAM for multitasking, which eliminates a number of otherwise reasonable possibilities. While gaming laptops will almost always take a memory upgrade, the lightweight productivity models often do not. Between that and the storage you'd like, I didn't see anything as good as the Envy for an equal or lower price. On the very high end, there are plenty of more powerful options, but your "variety of prices" might not extend to around $2,000, and that's a lot to pay for a moderate upgrade regardless.
One thing worth noting about the Envy is that it apparently doesn't get anywhere near ideal performance for its hardware in gaming. The graphics card tends to severely downclock under load, leading to around 10-15% slower performance relative to other laptops with the same card. That may or may not matter to you in the context of Sims 4, but if you happen to be doing graphics rendering, you could see a similar effect. This issue could apparently be fixed by adjusting the card's power settings, but that's assuming the settings are even accessible and that doing so wouldn't damage the laptop. (This is the kind of thing you let other people try first, for sure.)
If you're interested in other not-a-gaming-laptop options, these two are £1,200 and have the same hardware: an Nvidia 1650, capable of running Sims 4 on ultra graphics settings with some room to spare; 16 GB RAM; and an i7-10750H processor. The CPU is significantly faster than the one in the Envy in tasks that use 4 or 8 cores, although again whether this matters to you would depend on the load you plan to place on the laptop. (Sims 4 wouldn't use the extra power.) These two do only have 512 GB storage, and they're heavier, at just under 2 kg each. So whether the tradeoff and higher price tag are worth it may be a close call for you.
https://www.currys.co.uk/gbuk/computing/laptops/laptops/lenovo-yoga-creator-7i-15-6-laptop-intel-core-i7-512-gb-ssd-moss-green-10208589-pdt.html
https://www.dell.com/en-uk/shop/laptops/new-inspiron-15-7000/spd/inspiron-15-7501-laptop/cn50101
I was all set to recommend the Asus Zephyrus G14, a gaming laptop that doesn't look like one and is smaller and lighter than almost anything else on the market, but I realized it doesn't even have a webcam, which is unfortunate. Just in case you're curious, this is the £1,200 configuration:
https://www.overclockers.co.uk/asus-rog-zephyrus-g14-ga401ii-nvidia-gtx-1650-ti-16gb-14-120hz-ryzen-r7-4800h-gaming-laptop-lt-2a7-as.html
Anyway, the short version is, the Envy is a great option for your other purposes and a decent but not ideal one for Sims 4. If gaming matters enough that you want an upgrade, there are options out there that would work, but if it doesn't, the Envy will certainly be good enough to run the game; you might just need to make some compromises on the graphics settings.
If you have more questions, or you want to talk about more expensive options (at least over $1,500), let me know.