Confusion exists here because both Module Activity: Load and Process Activity: Inject with injection_type_id = 2 (Load Library) can be used to represent an endpoint process loading a module.
Process Activity: Inject with injection_type_id = 2 (Load Library) represents when an actor process acts on a target process to cause that target process to load a module.
Module Activity: Load covers the more general case of an endpoint process loading a module which is something that endpoint processes routinely do.
Given that Process Activity: Inject with injection_type_id = 2 (Load Library) is more specific, it should be used if applicable.