It's almost disingenuous for the original aartlice to be posted. There are so many posters, who are making wild comments, without any real insight into this issue.
Can I spell it out?
1. Apple have not recently chosen not to allow this app, Epic's account with Apple was terminated a number of years ago.
2. In the US, as it stands today, Apple are not required to permit any app that wants to go into the App Store, and onto a device. Nor is it required to have a facility to allow 'sideboarding'.
Protecting the interests of the company, the shareholders, and the country, alongside protecting customers, by having a safe, private environment, has always been there priority. You are not forced to buy from Apple, and whilst they don't have a monopoly on smart phones, operating systems, and games, that they are not legally forced to.