I have never had a project manager who did not have software development skills and experience. It really doesn't make a difference: they still need to trust the team they're leading.

Developers need an appropriate level of authority.

Building something safety-critical? Every dev needs to be able to "pull the rope and stop the train" if something isn't right.

Building a toy? Kick the "this is fragile, should we do it?" questions up to the PM.

I don't want my devs deciding to arbitrarily gold-plate every trivial feature, but at the same time, if there's a latent quality problem, I need to know about it.