Welcome to the club, I have moaned about this type of performance for years. The higher resolution screens, 30" or even 27 inch cause a lot of problems with LR on 100% views, now add either around 10 adjustment brushes, or 20 dust removal and go have a cup of coffee. Or use the auto mask, and then attempt to refine some of it's mistakes, which creates a ton of speed issues. It can become so bad that even once zoomed to 100%, then attempting to move the image will either crash LR or takes 20 to 25 seconds to refresh, just a bit frustrating. And minimizing the LR window to a smaller size on a 30" screen used to help, but no longer seems to make a bit of difference, so possibly things have gotten worse. I have the same resolution on my 30" screen as the OP.
The use or non use of modern, fast, well designed video cards and open CL is basically a waste also. LR/Adobe states only the develop module has been written to take advantage of open CL, but I have never seen any difference on or off. Unlike Adobe's own software Photoshop, which has an excellent design around open CL, and you can clearly see a difference visually and in a speed bench.
I believe some find the Problem is the same on the Mac, I have read enough similar complaints from large heavy lifting Mac users.
I have also given up on LR fixing this issue and work accordingly, trying to keep adjustment brushes to a lower number and no spot removal, instead go to CC for that. As all digital files get larger and larger, this problem will just get worse. But I notice on really anything 24MP and up with the conditions I previously mentioned, which is tragic as LR has an excellent tool set, one of the best.
LR is much more processor based, and system ram, so best thing I have found to do is possibly overclock a bit, turn off open CL support in LR as it eventually causes more issues over time. And reboot after about 1 hour 2 hours max as LR seems to build up a lag over time, not sure if it's memory leak or just coding.
Both machines I have are win10, 32GB of ram i7 4 and 3.6GHz, both with nvidia GTX970 4GB cards. You can benchmark LR on any of several open CL tools and there is literally no increase is the cuda processing needs, memory use, or need to increase fan speed to to work, the card just does basically nothing. Same testing Adobe CC and you can see quite a bit of activity on the card.
Paul C