No need to apologize - this has been a great discussion all around and I appreciate everyone’s thoughts, suggestions and input, and I’m happy that it continues to inspire people to think about upcoming builds.
I do have a few thoughts/comments about combo of the iCue Link Titan 360 RX and the Corsair Frame 4000D case though, at least if you plan to top-mount the radiator. As you can see from my case photos, I mounted mine such that the coolant tubes route to the front of the case. I did this because mounting the radiator the other way around cause the tubes to interfere with a rear-mounted exhaust fan, which I wanted to include.
HOUWEVER … the iCue Link port is on the same side of the radiator as the coolant tubes. In addition, the way the Frame 4000D;s mounting points are situated, the radiator’s forward-right mounting point results in very little clearance for the iCue Link cable between the plug on the radiator and the glass side of the case. If you’ve used iCue Link stuff before, you know Corsair tends toward low-profile 90 degree connectors, with the cable oriented in line with the straight part of the plug (so the plug forms a little L-shape at the end of the cable). This is normally no issue but in this application, with the plug end towards the glass side of the case, the cable comes out pointing to that glass side. Turning the plug around to mount with the cable running into the case is impossible because the radiator coolant tubes are installed on 90 degree angles pointed down and there’s simply no room to fit the cable in that orientation. In short, no matter how you attach that iCue Link cable to the radiator, the cable will have to be bent fairly sharply to fit. Fortunately, I managed it, and it works fine. But it was a hiccup that Corsair could avoid by providing at least one Link cable in a different plug configuration (e.g., a low-profile plug where the cable comes out the bottom - a T shape, rather than an in-line L shape, or a simple straight-in cable). Alternately, designing the radiator to move that plug connection further inboard on the end of the case to create more clearance between the plug and case side would also improve things for use in a mid-tower case like this.
Sorry if this description is unclear - I can provide some pics later if anyone wants to see what I mean.
But as I said, this works, and it works fine - even without under-volting the CPU, or doing any tweaks or changes to iCue’s “Balanced” cooling profile or messing with the front case fans profile via the motherboard BIOS, the system did a full run of Cinebench 2024’s CPU All Cores test at between 78-80C. With a -10 PBO curve, it did the same run at 73-75C. I will tweak the case fans to ramp up a bit faster and experiment with a lower under-volt. Some videos I watched suggested an all-cores -20 was stable on every 9800X3D he has tested it on but I will likely just try -15 as suggested above and if it’s stable, leave it there. I don’t want to spend weeks hyper-optimizing, I just want it stable, fast and cool, then get back to simming and gaming. 
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