When inconsistencies arise in moderation, or when flags go ignored, I would usually have a discussion with my moderation team: where do they need more manpower? How are they coping? I would then promote active, reliable users to TL4 or category moderators on a probationary basis to assist with such matters.
Related Topics by ai is really helpful in this case, since it provides relevant topics which sometimes contain the answer. One of the downsides when there are too many related topics, then the suggested ones are simply echoes of the current topic.
I would bump really old topics that contain useful answers, and prune the duplicates (by merging or deleting them).
I’d be interested to hear what other people do.