I could see Apple investing a comparable amount of money into chip design as AMD. Back in 2011, they had
a thousand people working on chip design and
in 2019 they picked up 2,200 people from Intel to do wireless chip work. AMD have around 12,000 people, not all of them are likely to be chip designers given there needs to be folk to do finance, marketing, investor relations, security, software development and more in that number. It's not inconceivable that Apple actually has a head count for silicon not too far off AMD's actual number. I agree nothing guarantees it
It's also useful to put in perspective that Apple probably sells more chips than AMD does when you tally up the iPhone, iPad, Apple Watch and Mx series devices they sell per year.