The i9-13900 (Non K) was not introduced as the die size was relatively larger than the flagship Alder Lake processor. You can thank the other Gracemont kernels for that.
Expreview at Bilibili has removed the integrated heat sink (IHS) from the alleged i9-13900. As shown in the figure, the die specifications are about 23.8mm x 10.8mm, which corresponds to a total die size of 257mm², which is about 23% larger than the 12900K.
No, you don’t need excessive technique for this purpose. To remove in this case, it just took a razor and a heater. However, keep in mind that leading removal is a very delicate and fragile process where even a small mistake can render your CPU useless. Most people or enthusiasts were looking to make their CPU cooler, as shown when Linus dropped his i9-12900KS .
Intel is rumored to be planning to unveil its 13th generation processors on September 28th during its innovation event. Intel is expected to reveal the specs of these SKUs along with pricing. The estimated launch date for these processors and the flagship Z790 motherboards is October 17th.