The author of a piece of fiction should not necessarily know the “truth” about the story or the characters.
Characters should lie. Characters should have incorrect memories of the past, incorrect perceptions of the present and incorrect predictions of the future (these points about the knowledge of characters can apply whether or not the author knows the whole truth, so they are something of a tangent here).
The reader can end up with a different opinion to the author even after the end of the story. This is a positive quality to aim for.
Frequent examples of this in Gabriel García Márquez’s fiction. The reader is given a strong sense of an independent world and events, of which the writer is merely relaying the small part they are aware of.
A simpler and more extreme example is Raymond Chandler apparently not know who murdered the chauffeur in The Big Sleep.
The effect can feel lazy if it’s overdone, as if there was insufficient effort in thinking through the fictional world and events in it, with the story being thrown at the page instead.
If that can be avoided, the idea is valuable. The author does not have to be the arbiter of truth for the story, only the teller.