Fortnite is an open world game with 100 players.
The video mentions there were some things Pg wanted to cut back but weren't allowed to
'Fornite' is made by the creators of the engine, so they have a big margin for including custom modifications, optimizations.
And the geometry in the characters of 'Fornite' is not even comparable with your normal PlatinumGames games, or their fucking gigantic bosses.
'Bayonetta 2' is much more advanced from a technical standpoint than 'Fornite', and it's running on 60 FPS instead of 30 FPS on Switch.
Unreal Engine 4 has been a recipe for disaster and delays this generation, regarding third party studios.
A game with the scope of 'Batman: Arkham Knight' is running in a modified version of Unreal Engine 3 and not in Unreal Engine 4 for a reason.
And all the delays of 'Yoshi's: Crafted World' are related with the hellish experience of trying to optimize this to achieve 60 FPS. Compare this with a custom engine like the used on 'Donkey Kong Country: Tropical Freeze': more 3D elements on the scenarios, a resolution almost close to native on portable mode and 60 FPS.