I still can't decide.

Anecdotally the very best and the very worst managers I had were not technical. Instead my technical managers, think ex-engineers, were on average from mediocre (new to the role) to good (experienced).

I built a mental model that the difference between non technical EMs and technical ones is that the distribution of quality is broader for the former. I suspect people skills is the real leverage.

Anyhow engineers have little influence on deciding which kind of manager they are gonna get, so it's better to focus on what we can control and learn the secret art of how to manage your manager.