If Tom Clancy's Ghost Recon Wildlands generated the same gross revenue on the Epic Games Store, Ubisoft Paris, Ubisoft Annecy, Ubisoft Bucharest, Ubisoft Montpellier, Ubisoft Milan, Reflections, Ubisoft Belgrade would keep approximately $99,959,371 - that's $12,196,306 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $13,494,460. 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 $79,417,682.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.