ICAO was created to get a form of internationally agreed rules in civil Aviation , as well as covering international airspace . It is mainly standardization body ,and some annexes, like Annex 13 are not their priority, The priority is PANS OPS and PANS ATM, and that works relatively well. and keeps us safe when we fly
As to accident investigation reports, although there is a template , there is no guarantee the contents will be useful . I have seen some reports of a few pages but where every question is answered, but tells you absolutely nothing , to 400 pages ones .But in the end , the analysis is what counts. The problem today is that insurance lawyers ( sorry Willow run ) are looking for clues to blame someone to get either their clients off the hook , or just make money for the families ( and themselves) . That explains partially why some recent reports keeps things vague if the investigators are not 100% sure of a fact. Bad for safety and we may be missing important clues as a result.