Not just the degoogled open source Android disros either. Amazon has a commercial fork of Android with its own app store. There was Oppo's AOSP derived ColorOS which was not based on Google's stock Android. I don't think Google should control the core apps as tightly as they do on stock Android but on the other hand those apps sort of define stock android and the default user experience in the marketplace. Epic could roll their own fork if they wanted and substitute apps.

On the subject of Oppo, I think Tencent went after them and other Chinese manufacturers as well to get into their platforms. Tencent are the guys who push their own app store and one app to rule them that Musk has wet dreams about. I sometimes wonder if they are using Epic to wedge open US based app stores for a future WeChat/MyApp like approach. Not that the US government would allow that.

Valve created their own console and helped fund Wine development, presumably as a strategic move to counter Microsoft's platform control. I might be missing something but I don't see similar effort or innovation from Epic.

I believe Microsoft and Nvidia did deals with hardware manufacturers for years that helped exclude competition and those sorts of deals probably pose more difficulty in court. Google might have fallen into a trap and done something similar. Being vertically integrated Apple doesn't have to do deals with other manufacturers but presumably they have some deals with developers. Obviously Sony, Nintendo have exclusives, agreements with developers and tight control of their platforms as well that go far beyond anything I can see with Google so I do find it a bit confusing.