Huh? I don't play any Epic games... But just because they refuse to pay a 30% fee?
Apple is only the distributor here. If they would charge a reasonable processing fee (4-5% like credit card companies do) nobody would have had - presumably - a problem.
Unlike with most (all?) other platforms there is no way to install apps from any alternate sources.
30% is the modern version of way-laying. (IMHO at least)