MediaTek may have a winner with the Dimensity 9400 as the company's "internal testing progress is good". The SoC is rumored to have a more impressive IPC than the competition. The latest leak also reiterates the Dimensity 9400 to be based on CPU designs from ARM.https://www.notebookcheck.net/MediaTek-Dimensity-9400-IPC-advantage-over-Snapdragon-8-Gen-4-and-Apple-A17-Pro-leaks.832319.0.html
Qualcomm has had custom cpu cores in phones over a decade ago, lookup scorpion and krait.