Which step are you counting as "manufacture"? They will have a lot of partners here in the supply chain of this component; ams-Osram, LG, and TSMC according to the article.

In terms of Apple being "hands on" in manufacturing I don't see this as too different from the Apple Silicon case, where they design but work with partners in Taiwan+China to manufacture.

I see the big news here as "moving away from Samsung", where they would likely have to continue to invest in a competitor (money and IP) in order to get microLED technology through them.