Better sale opportunities at Epic Games or Steam?

I’ve released a game with Epic First Run program (“A Journey Rediscovered - Intro Version”), and while my demo version has sold hundreds of sales for free, the base game hasn’t been bought once.

I know the First Run is supposed to enhance the promotion of my game, but if I can’t sell at least 10000 base games, nay, even 1, then I’m definetely moving over to Steam. So how can Epic Games be better than Steam?