If Like a Dragon Gaiden: The Man Who Erased His Name generated the same gross revenue on the Epic Games Store, Ryu Ga Gotoku Studio would keep approximately $11,345,367 - that's $2,278,293 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $1,410,732. 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 $8,929,269.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.