Technical managers should I think have done some of what they are managing, so coding if they are managing coders, and it's good though not always practical to

Technical managers should I think have done some of what they are managing, so coding if they are managing coders, and it's good though not always practical to keep one's hand in. OTOH, I have had a couple of data scientists working for me, while I was/am definitely not qualified to do their job! But I strongly respected their work...