I’m not sure if anyone has resolved their issue, but I recently followed this documentation which provides a method for implementing an ocio.config to be active at runtime:
If you’re using either the first or third-person template you can modify their main character blueprint and add the custom blueprint underneath the existing cameraBoom or manually create the variable inside it and connect it to the eventPlay, as well as activating the config in the camera’s Details tab.
The colours and exposure between the level and different play editor modes are not 100% working correctly for me at the moment, but still testing some settings. This is using AcesCG v1.3 ocio v2.3 based on the cg config v2.2 provided by the AcademySoftwareFoundation from their GitHub release page:
First screenshot is with level editor and post-process volume settings. Second screenshot is at runtime (selected viewport) mode. Third screenshot is when attempting to run as a Standalone Game mode, lol.
The display destination I assigned between the level editor, the blueprint and inside the thirdPerson blueprint is Rec.1886 Rec.709 - Display - ACES 1.0 - SDR Video.