Do you consider the usage of oligopolies optional? I could live the life of stallman, but this decision kills an amazing user experience for subscriptions.

The European commission has you covered on the oligopolies side.

It's not killing user experience at all, if the user want, they can use the App store, because few if any app will ever make a complete move away from the App store, it would cost them way too much. The only ones that could pull such a trick are DMA's “gatekeeper” apps and they are under scrutiny from the EC, so you're safe here.

(Well, Fortnite doesn't fall under DMA's 10 “gateway services” that deserve scrutiny from the DMA, but their alternative store will!)