I would add to nixpulvis’s comments that git history may also help you find a repro case, especially if you’ve only found a half-assed repro case that is overly broad.

Before you find even that, your fire drill strategy is very very important. Is there enough detail in the incident channel and our CD system for coworkers to put their dev sandbox in the same state as production? Is there enough if a clue of what is happening for them to run speculative tests in parallel? Is the data architecture clean enough that your experiments don’t change the outcome of mine? Onboarding docs and deployment process docs, if they are tight, reduce the Amdahl’s Law effect as it applies to figuring out what the bug is and where it is. Which is I. This context also Brooks ‘s Law.