Got it— prioritization of say features vs prioritization of tasks in the backlog, as an example. Management is necessary— I don’t think management’s function to a company can be discounted. I am advocating for certain traits I think a manager ought to possess, one of which being they have full ownership of everything happening under their umbrella. :-) Not saying they have to code, but saying if necessary they can be a substitute for anyone under them (given some minor startup cost).
The problem is that the world is not filled with superman. People who can code, lead, manage down, manage up, do product and so on are very rare. Ones who can do all those well are even rarer. By focusing on coding you get people, who to be blunt, can't manage or lead well. Which leads to more conflicts and issues than it fixes in my experience. Even if you find such people you get into the problem of them stepping on toes because they or others don't realize which hat they're wearing at a moment (ie: are they talking as an IC or as a manager).
Plus, at the end of the data, a good manager should aim to hire people smarter and better than them. If they can step in for those people quickly then they're not hiring better or smarter people which is a problem. A first line manager should understand what people do but that is different from being able to do their job to the same level.