You're largely just going to lose the people that are genuinely trying but just aren't as productive for whatever reason and give legitimacy to those who aren't

You're largely just going to lose the people that are genuinely trying but just aren't as productive for whatever reason and give legitimacy to those who aren't as honest who will learn how to game the metrics to defend their jobs. The former can be mentored and made more efficient, even with 2 hour lunch and prayer breaks, while the latter will just dig themselves deeper and cost the company more and more. Meanwhile, your best people who can find another job anywhere will leave immediately because they don't have to deal with the changes.