If Ghost of Tsushima DIRECTOR'S CUT generated the same gross revenue on the Epic Games Store, Sucker Punch Productions, Nixxes Software would keep approximately $75,228,694 - that's $9,948,063 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $10,122,095. 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 $59,745,552.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.