The D15 on my main system is cooling an overclocked 6800K. I'm pushing it as hard as I can and even when I was trying to get 4.3HGHz out of it and pushed it to 1.5v it stayed under 70 degrees, and it's still pretty quiet. Nearly silent at idle. I've been more than happy with it, but I have my doubts about even the best air option from Noctua for TR4 is good enough to push it, and I do overclock. Even some of the better AIOs are having a little trouble.
I've never much cared for them and while I've done custom loops for other people, I've never done one for myself cause while they look great, I've never seen a practical need for my usage. These new Enermax AIOs might change my mind about AIOs though.
I'm going to move to Threadripper. I wanted to get one of the initial ones, but then I heard about the Zen refresh and decided to grab one when they incorporate those. AS it sits, your 1800x kills my 6800K. Threadripper would probably cut my encode times in half.