There's a big difference. First of all, in terms of process technology, usually the smaller the value, the more transistors can be put down in the same area. The 6nm process has an 18% higher logical density than the 7nm process, which means that under the same number of transistors, the chip area using the 6nm process will be smaller, which will provide more space for the phone body.
The process is different, 6nm is smaller than 7nm, lower power consumption, and stronger performance.