2021 royalty revenues were up 20% to a record $1.54Bn, helped by continuing strong growth of 5G smartphones, more ADAS and IVI chips going into cars, and price increases in 32-bit microcontrollers."
Source: https://www.arm.com/company/news/2022/05/arm-delivers-record...
The royalties are higher on the newer more complex designs, so the 29.2 billion chips number can't really be used to derive a proper price per chip.
Don't even get people started on the perpetual and architectural licensing too.