If Sekiro™: Shadows Die Twice - GOTY Edition generated the same gross revenue on the Epic Games Store, FromSoftware, Inc. would keep approximately $242,497,970 - that's $25,154,361 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $32,931,541. 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 $192,800,658.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.