Sounds about right. The system drive should be an m.2 NVME PCIe - these transfer data at 4X the rate of a fast SATA3 SSD.

I am still a fan of a pair of 1920x1280 displays - you end up with 4K when you extend the desktop, and you don't have to play around with scaling to get the text to a size that you can read easily. I use an old pair of Dell displays - the current version would be the UltraSharp 25 Monitor with PremierColor - UP2516D. It has a programmable LUT and can display over 1B colors - and 1024 shades of grey, for precise and accurate color/black and white images. You will need an Xrite i1 Display Pro profiling tool to be able to write the profile to the display. if you get an Nvidia Quadro 2000 or higher, (maybe the 620 will also do it but I haven't tried it) you'll be able to display 10 bit color in Photoshop, or any other application that supports that bit depth.

Are you sure 2TB is enough? Since you are having it built, you'll have more than enough expansion space, so you should be able to stack at least 6 internal drives in the box. Make sure you get some form of liquid cooling so you can take advantage of the "K" designation on the cpus you are considering - the K means you can overclock, hence the recommendation for extra cooling. Also make sure the builder matches the RAM speed to the cpu. Get 2 16 gb ram modules so you can add another pair later for 64 gb ram. More than likely that will be the only future proofing you'll need to do. Otherwise you should be fine.

I am in the process of selecting parts for my next build, and I am coming up with a price of about $2K, which is not terribly expensive for the outrageously fast machine I will end up with. Good luck with yours!

You might like looking that the Puget Systems website. They build custom computers, and their website has a lot of excellent information on recommended components and discussion of why those were chosen. Of course, you don't have to go with exactly what they are using, but it makes a good guideline.

https://www.pugetsystems.com/

I did some upgrades to my desktop computer last year and Puget's website was a big help.

The SSD should be no less than 500GB, and this is where you will store your operating system and all other programs that you use on your system. Your internal HDD should be at least 4TB so that you are not likely to run out of space any time soon. This is where all your documents and photos will be stored.
The HDDs need to be good quality, such as the HGST Ultrastar, which has a 5 year warranty. I also use another 4TB HGST Ultrastar as an external drive for backing up photos and documents, installed in a case with a fan. It is easy to do, just insert the drive and plug it in! More than one backup drive is recommended - I have another 4TB WD My Book for backups. I use a Dell Monitor 27" and I like the size very well. I also have space limitations! The one I use is an UltraSharp IPS monitor.

Additional things to consider: Adequate size power supply, dedicated graphics/video card, motherboard.
The nice thing about a desktop is you can have more than just 2 internal drives if you want. The most important thing is compatibility of components. When I did the upgrades, I was limited to choosing components that were compatible with my motherboard, which I was not replacing. Eventually it will get replaced as well, because it is older, and then I may also end up having to also replace the RAM, depending on the motherboard I will install.