From my experience, GPU is entirely irrelevant because Phoenix virtually does not use it at all -a 5% usage was the highest I ever recall seeing it - which is a real bummer because it could speed up certain processes by a considerable factor. So a fairly middle-of-the-road GPU will serve you fine.

64GB of memory is on the low end. I’d go for 128GB. Phoenix usually does not go above 64 GB but there are certain processes on my workstation that will consistently push it above it into the 72GB range. Again, it’s a shame that Phoenix does not make full use of the resources of the machine. The extra memory should/could really serve as cache memory, etc. I should also mention that Phoenix can become very unstable under memory pressure!

The more cores, the better. Phoenix still does virtually all processing on the CPU and most processes are multi-threaded, so the cores are all put to work. There are some DVOs that still do not take advantage of the full cores, but they are far and in-between. So faster CPU clock and more cores are what you want.

Disclaimer: All of my work involves uncompressed 4k DPX source, intermediate and output files, which are by nature extremely memory and processing intensive. If you work in a different workflow your mileage may vary.
 

Just a quick note about the GPU again. I've been using this GTX3060 graphics card in my system for the past 2 years and it gets the job done perfectly fine — at a third of the cost of the card you have on your wishlist. Its usage never climbs over 5% and Phoenix uses virtually no GPU memory, so even the 12GB are overkill. 

https://amzn.to/4i1wkOp

In terms of the motherboard/CPU combo, I'm currently tempted to try out an X99 dual-CPU i9 board that would allow me to put two i9 14900K processors in it—a CPU that is almost identical in performance to the Intel Core CPUs. In theory, that should provide some serious processing power for Phoenix at a very reasonable cost. However, I've heard good and bad things about these motherboards, so I'm still on the fence—just as a personal sidenote for you to consider. You could use the money you're saving on the GPU and, instead, put it into real CPU power in that case, which should make a notable difference in Phoenix's performance.