Number one in performance / watt? maybe? sales? Well no. According to the web[1] total chip sales in 2022 excluding arm amount to 374 million units. Server chips being 36.1 million units. Apple's biggest quarter in 2022 was 7 million macs in Q4[2].
For anyone curious, iPhones ship 234 million a year, Watch around 60 million, iPad another 20 million. Not sure about Apple TV but let's assume that's 0. That's over 300 million CPUs a year.
I doubt the total chip number for the industry though - Intel alone ships ~100M. But it's clear Apple is very likely the largest manufacturer of CPUs.
* Correction: MediaTek shipped 350M units in 2020 and Qualcomm shipped 319M (due to the Trump embargo on China). So Apple is up there competing with manufacturers that sell their chips to anyone who will buy, but it may not necessarily be the largest.
Yeah. How you count things is very subjective to where you draw the line. As for margins it's hard to say because Apple doesn't sell chips independently so their profit margin on a chip is withdrawn from however they want to distribute the profit margins for the entire product and Apple does not provide a breakout a sufficient level of granularity into the financials to understand that.