Epic decided to take a cut from gross, because if it’s from “profits” there are too many accounting tricks that unscrupulous people would try to use to withhold payment. From an accounting point of view, this makes total sense! Note that, if you give the game away, you will charge zero dollars, and thus owe zero dollars. (This doesn’t hold if you “give away” the game but it requires the purchase of, say, a custom controller. No cheating the system!)
You have to make the business decision to price your game such that you can afford the Epic cut, once you make a million dollars in revenue. If you somehow think that you can’t do this, you’re free to use some other engine and adhere to whatever their rules are. Similarly, you have to choose a store or marketplace, and a price for that marketplace, that makes your business work out. Godot, for example, charges exactly zero dollars. (But if you make a profitable game, sending some amount to the developers, would be the right thing to do, to sustain the development.)
“But Godot doesn’t have close to all the cool stuff that the Unreal Engine has,” you might say. Yes, you are correct! This is how a market economy works: Producers produce products, and charge prices that they think are reasonable to pay for that production. If you produce a better product, you charge more.