I think you're sort of wrong here. Epic would likely be just fine with sideloading Fortnite and handling the distribution themselves (like they did with Android). What they're contesting is that only Apple is allowed to sell software on the phone, and in doing so also collects 30% of the cost. Apple could just get out of the way but chooses not to.
Okay but here's the thing. Such a change is good for the app publisher at the expense of the customer except in some vague second order effect about improbable price improvement.
Right now you have no choice but to buy Fortnite on the App Store. In the future you will have no choice but to buy Fortnite on the Epic Games Store. Customers don't really gain anything here.
I'm sympathetic to the whole software freedom angle and that end-users should be able to run whatever they want on their devices unrestricted but I could care less about publishers wanting to get around Apple's platform fees and store rules which for all their flaws genuinely benefit me as a user.
Like it sucks that it took total control, thousands of human reviewers and an iron fist to keep companies from getting away from bright line screwing over their customers but here we are.
You are ignoring the world of products that Apple prevents using their control over the App Store, which they absolutely do use to exclude or hobble competitors and stifle controversy (such as how they have pulled multiple apps that were commentary about smartphones being made in sweatshops). Apple is already past the "live long enough to become the villain" half of "you either die a hero or". The anticompetitive effects of having a duopoly--both of whom being interested in complete vertical integration--in control over all software distribution is devastating, and it isn't just some improbable/vague second order effect (which is also a ridiculous assertion even for price improvements: there are tons of products that are having to charge more only because of Apple... mine is one of them! it really depends on the app's sales mechanism whether 30% is fair or not, and this is coming from someone who has run a successful competitor to Apple on their own platform, despite the users having to be rabid for it due to how many hurdles they had to jump... before Apple finally "won" :/).
If so, many thanks to you for your labor of love. I have been jailbreaking iPhones since 2012 with your help. I'm sorry that the corporate structure railroaded you.
Epic can just offer their app in both Apple's store and its own store. It's just that Apple store prices will be higher according to Apple's commissions. If you like convenience of only using Apple's payment services, who's stopping you from buying it in App Store with higher prices?
If Apple rejects the app from being available in its store, then again that doesn't affect you because you want to use only Apple approved apps anyway.
