Games DRM free on Epic, and to be DRM free, by definition, it must launch wwithout Epic Store Client, using main exe, no need to run direct from the IndianaEpicGameStore-Win64-Shipping.exe
This much shorter path, runsw the gamne without Epic Store Client <path-to-game>\TheOuterWorlds.exe
The longer path does work, but it's not required. <path-to-game>\Indiana\Binaries\Win64\IndianaEpicGameStore-Win64-Shipping.exe