If The Elder Scrolls IV: Oblivion Remastered generated the same gross revenue on the Epic Games Store, Bethesda Game Studios would keep approximately $50,406,443 - that's $7,691,495 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $6,737,242. 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 $40,000,580.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.