Why would you want to game metrics that honestly can help improve your business outcome? The study is worth reading and to put it simply: the metrics seem to make sense anyway and if science proves that they do, that’s even better.
Science doesn't tell us anything (that would be authority or religion), and it doesn't prove things. It is a process that can assist us in logically determining what is NOT true about a cause-effect relationship to the point where we can make more accurate and practical predictions about those causes and effects. More experiments refine the current beliefs.
Q: If your manager imposed OKRs/KPIs on your team, especially if there were a financial incentive linked to achieving "results"/"performance indicators", how would you feel?
Note that what is good for the business may or may not have much to do - at least in the short to medium term - with what is good for the employees.