If Wolcen: Lords of Mayhem generated the same gross revenue on the Epic Games Store, WOLCEN Studio would keep approximately $49,414,303 - that's $7,601,300 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $6,601,950. 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 $39,211,377.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.