Asklemmy

Imho, the most important trait a good manager can have is humility - by this I mean they don't let that management position go to their head and realise that everyone's in the same pot, they have the capacity to admit when they're in the weeds in terms of knowledge and are not afraid to ask for clarifications or to let someone else take the wheel in specialty aspects (and not as an excuse to stay ignorant), and that they're not the most important person in the team, the entire team is.

Besides that, transparency in all things, empathy (we're all people with people stuff going on in the background), honesty, diplomacy, genuine curiosity, a capacity to see the forest for the trees, the courage to put their foot down when absolutely needed (mostly to defend the team), accountability, doesn't micromanage but instead encourages their teammates to develop both their skills and confidence in their skills.

As I see it, a management position should exist to help the team, not lead it. People usually know what they're doing (most of the time even better than the manager), so the manager should ensure that they're working on providing things which are in lesser supply within the team (eg. can function as a spokesperson, simplifies the processes in order to remove needless time sinks, can ideally act as a quasi-therapist for all things work related, keeps track of the big picture, helps structure the workload in a rational manner, etc.).

Edit: oh, and this is a personal favourite of mine, is not afraid of saying that the ship's sinking when it is. Again, working for what's best for their teammates.