Sorry for the delay coming back to this thread, busy weekend. That is all excellent info! Not that that's surprising

I almost didn't ask this question but now I'm glad I did.
I'll have to ponder a bit more. I can get the 9950X3D, a 5080, and 64 GB RAM in his budget, so I could go top of the top in one sense, but I get the point about the value for use consideration. He isn't going to be doing anything that will likely make use of all those cores. It'd just be cool to get him the "best of the best" so to speak since he's chugged along on the 4970K for so long.
The heat is a consideration for the 9950X3D too though. I'd like to get the Thermalright Phantom Spirit Evo again because I've been impressed with that one for the easy install, and the cooling on my 5900X and the recent niece's 9900X build. But I'll have to research I guess if it'd be up to the challenge if I did go with the 9950X3D. 9800X3D for what he is going to use the PC for is likely the most sensible.
I will definitely avoid the 9900X3D though. Thanks for pointing out the issues with that chip.