CPU specs are really kind of plateauing, and the push is toward multi-core. If you’re looking at desktops, I think you’ll get more bang for your buck with more cores and an older processor. Buy the one that was $15,000 and top of the line five or six years ago but is a fraction of that price now…
I think the next computer I get will be AMD because of all the horrible security issues with Intel processors but I’m not totally sure. I just upgraded my laptop to a 2015 thinkpad last year and don’t expect to replace it anytime soon. The older models in the AMD “threadripper” series are getting pretty cheap though.
Also: give linux a chance if you weren’t already thinking of it!
If you’re running linux a five year old i-series Intel CPU with 4 threads and 8GB of RAM is tons of horsepower. This is the CPU in my primary computer, an x250 thinkpad: https://ark.intel.com/content/www/us/en/ark/products/85213/intel-core-i5-5300u-processor-3m-cache-up-to-2-90-ghz.html (Which was ~$200 when I bought it about a year ago.)
Windows, I don’t know. You might be fine with something similar?
The NUC is cool too but if the size isn’t very important, you can do much better for much cheaper building a normal sized desktop tower… the difference between my $800 NUC and my $200 thinkpad isn’t so huge. I have the NUC mostly for shows and installations, although it’s nice having a dedicated render box in between!
Edit: also, while you consider it… maybe pick up a raspberry pi 4 & heat sink, overclock it and add an SSD and give that a spin for a while? They are surprisingly capable machines.