If V Rising generated the same gross revenue on the Epic Games Store, Stunlock Studios would keep approximately $82,236,051 - that's $10,585,096 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $11,077,643. 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 $65,319,586.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.