The only bad managers I've ever really had are the ones that don't realize they're responsible just as much as their reports when shit goes sideways. To that point, I've had technical and non-technical managers and it doesn't matter, we can speak a different language but as long as we realize we're on the same boat and heading in more or less the same direction things are great. This requires trust, understanding of goals not implementation, and empathy.

Almost every bad manager I've had basically lacked at least two of those last three things if not all three.

I will say, the one big advantage of a technical manager is they can often be used as a good rubber duck for logistics around changes. Should we do {A, B, C} or {X, Y, Z}? You can get into the technical with them and explain the intricate trade-offs of the decision and how that might impact things. Their technical and political knowledge of the situation can give very good clarifying answers.