What Does a Software Development Manager Do Next?

If the team is as optimized as it can be, then it may be time to move on from this team to another where you can add value. This sounds like an obvious statement, but without knowing much about your organization this may or may not be a viable option.

But again to my original, what do you want to do? How do you want to grow? What impact do you want to have? If you have the organization structure such that you can make a case to join a new team and help them grow and/or help with strategy for the organization as a whole (which will touch multiple teams), then there is that path as well.

If you want to transition organizations altogether then the above still holds.. in the sense that you need to define your own goals and then find an organization where you can develop them and have an impact.