I took a look at a few videos on the 12900K based on this post. It's still pretty new and with PCI5, DDR5, there will surely be new hardware that takes better advantage of the new technologies. Therefore, the 11900K is a good solution for the next time
I had my sights set on the Ryzen 9 5950X, but since single core performance is important for Hauptwerk, the 12900K comes out on top. Let's see how the hardware optimizations around the 12900K develop.
My dream will be achieved when the hardware peripherals make it possible to play samples on the fly from the SSD without having to load the whole sample set into memory. I hope that by then some sampler will support this. It would be nice if Hauptwerk is that candidate...