Thanks for sharing, @Valeria_Koz_DBX!
For ownership, I (try to 🙂) favour a named business owner who validates the metric definition and expected answer, paired with a technical owner responsible for investigating the issue and checking the fix.
Confirmed misses can then become self-contained Genie benchmark questions, with reviewed reference SQL where appropriate. Rerunning those after changes gives the team a way to check whether the same issue has returned.
For me, the loop closes with the person who raised it: "Here's what changed and how we checked it. Does this now answer your question?" That gives them a chance to confirm the resolution, rather than just receiving a "fixed" notification.
Appreciate you raising such an important topic.