Symptom
Queried with a status filter, got 0. Read it as "no items in that status."
Cause
The filter value was an enum that doesn't exist (wrote APPROVING; the real value is IN_REVIEW). No error. 200 with an empty array.
Fix
Take filter values from real data, not docs. Fetch everything once and count the distinct values of that field. Done.
★ Count the denominator. In 0/N, if you don't know N you don't know what 0 means.