But normalizing any number is problematic. It depends on the job, and the specific individual. A warehouse packer or a burger flipper are unlikely to accomplish more by working less. So lets say each person can be productive for X hours per week. This number might be the same throughout the year, or it might go up/down, etc. It might be co-related to other things (pandemic, life events, etc). And then you have some people that can be productive for 80 hours / week. (I want to explicitly make a distinction between warming a chair for 80 hours versus actually producing something valuable.)
The tricky question is, what is the threshold below which you are considered a poor performer? And the corollary - If you are one of those outliers who can be productive 80hrs/week - Should you be compensated more than your peers? I know that if I was one of those outliers (I'm not), I would expect to get rewarded for being more productive.