Help with pc parts!

So I am planning on getting a 9060xt with 9600x I will be doing 1080p gaming. With mostly fps competitive titles and Marvel rivals. I do play story games time to time tho lately mostly playing indie games.

Now main thing is that I am stuck with ram.
My plan is to buy a 16gb single stick now and one in future as I need more and can buy more.

So option for me are: 6000MHz cl40 for $200-220
6000MHZ cl30 for $280-320.

Is it ok to get the cl 40 kit or is the difference worth going for the extra $100 cause from what I read online cl 30 and cl40 have 4-12% difference in 1080p difference.

I will ideally be able to upgrade and get new pc 3 yrs later but at the same time do need to build one now as my current pc is on its last legs.

Do suggest mother board for the same and other parts.

My budget is around 1500$. I am ok with Nvidia options. And when it comes to ram I would like to stick to one stick rn and buy one more in future.