I think this could be a maybe a way to assess the efficiency of the QA team, but I am skeptic of using it as a metric about estimating the number of bugs. This

I think this could be a maybe a way to assess the efficiency of the QA team, but I am skeptic of using it as a metric about estimating the number of bugs. This is because QA is there to help with reducing the probability that an important bug will happen to a real user. But the total number of bugs a system have is a sum of bugs found by developers + bugs found by QA + bugs found by average users + bugs found by power users + bugs found at scale/big numbers. The more we move to the right of this sum the hard is to replicate conditions to find bugs and so we move from finding to probabilities and risk management.