Apple has an architectural license that lets them build their own ARM cores:

https://www.electronicsweekly.com/news/business/finance/arm-...

It is very unlikely Apple uses anything from ARM’s core designs, since that would require paying an additional license fee and Apple was able to design superior cores using its architectural license.

Yep, Apple was a significant early investor in ARM. https://appleinsider.com/articles/23/09/05/apple-arm-have-be...