If Ancestors: The Humankind Odyssey generated the same gross revenue on the Epic Games Store, Panache Digital Games would keep approximately $9,314,315 - that's $1,978,251 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $1,133,770. Epic charges 0% on the first $1 million in annual per-app revenue and then 12% on the remaining amount. On GOG (30% cut), the developer would earn approximately $7,313,660.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.