So far I understood the following.
The US president wants to ban transactions with Tencent, because whatever. Now Epic games (owned 40% by Tencent) starts this fight with both Google and Apple, joined by Spotify, which has a deal with Tencent in China and owns shares of it which in turn owns shares of Spotify.
This fight smells to me as retaliation, showing the weight of Tencent (indirectly) and the ability to rally developers to, at the end of the day, eat into the revenues of Apple and Google's App Store cut. Moreover, the ability to own billing address and information, as opposed to receiving payment by Apple but not having said information, surely plays a role as well.