The 5% royalty is for a commercially released game, and you would give 5% of your earnings to Epic for each released game you have, but only occurs once the game is making money. Same thing goes for Kickstarter etc, you only pay 5% on earnings, so no you don’t need to worry about it while you are in development. So long as your game is earning money, you will need to pay the 5% royalty quarterly on each game.
Hope that makes sense… 