@jenjane If components were readily available right now, I'd probably suggest an Nviida RTX 3060 ti as your best bet. It's massive overkill for Sims 4—you could get away with a 1650, and even a 1660 ti would be overkill—but if you want to play at a high resolution and/or higher framerates, it's an excellent option. Sims 4 looks great at 2560x1440 and wonderfully smooth at >100 fps, although it'll have fps drops on any system. Point is, you can clearly afford better than you strictly need, so pairing this system with a lovely high-performance monitor sounds to me at least like it's worthwhile.
MSRP for a 3060 ti ranges from $400 to $550 U.S. depending on the model, so certainly less than $1k CAD, but that's not relevant if you can't actually buy one. It's said that inventory will probably be tight until some undetermined time in 2022, so paying extra for a faster card you can get now may be worth the price. A 6700XT is slower than a 3060 ti but still massive overkill for Sims 4.
How much extra you want to spend really does depend on how long you want to keep this computer and what else you'll use it for. But it also depends on whether you want the very best performance you'll notice (as in, you don't need a $2k graphics card if you won't notice the difference in-game, which you won't in Sims 4). For example, with a single solid state drive that's extremely fast but not the absolute fastest, Windows would run a bit slower, but that's on the scale of a few seconds at startup or when doing searches. If you don't need the best, you could remove the $90 980 Pro and keep the single 970 Evo Plus.
You also don't need 32 GB memory, and RAM is easy to install, again this is about getting the very best vs. something that's very close to it. You could save money as well on the motherboard, but that's a more obvious tradeoff: the better the board, the more features it has, and you never know what you might want in three or four years. So while you might never notice the difference, if you did realize you were missing a feature that the more expensive boards have, you'd need to rebuild the computer to get it. Whether that's worth saving $80 is your call.
Finally, while you could get away with a cheaper processor now and for quite a while, the stronger one would support a relatively faster graphics card in the future. If you're thinking you'd just build or buy another computer in five years, you don't care; if you want this to last, you care a lot. As an example, the strongest Intel processor from two years ago can't totally keep up with the fastest graphics cards available now, and while I can't tell you what will be around in a few years, I can guess that the GPUs will be significantly faster than they are now. So again, you can't know now whether you'd be missing out in the future; it's your call whether it matters.
There's no efficient way to pick a system integrator: you really need to read reviews, or price comparable builds, or both. Local stores are often a better choice just because you can take the system back for adjustments if necessary, but you shouldn't need to do so. If you want to compare online stores, these two might come out cheaper but don't give you the same flexibility to choose components:
https://gamertech.ca/collections/products
https://www.gamingpc.ca/purchase.php?pcID=7
Finally, it's sweet of you to offer to leave me a nice review, but I do this for fun and because I think it's interesting, not as a job.