[Sarah G.]  Increase in business value over time. Business value can be decided in five sectors:
1. Commercial
2. Market
3. Customer
4. Efficiency (usually related to tech debt)
5. Future

Number of outages at different severity numbers
NPS
ENPS
Time to deploy a new feature (DevOps processes)
Number of interrupts an engineer experiences (do you engineers get time for hyperfocus)

[James pels] Value delivered. Measure the outcome, not the output.

If you see a particular challenge, by all means, get clever... one fellow coach of mine saw a team consistently failing to break stories down. He tried an experiment and got management to temporarily introduce a velocity metric, knowing the team would game it. They did game it, by breaking stories down. He could then work with them to refine work properly. Job done, and the velocity metric went.

Important bit here is that the metric on work was short-lived and for a specific reason: if metrics like this hang around outside the team context, they cause all sorts of issues.

[Lars Devocht] To offer insights into team performance, begin by leveraging the inherent transparency of Scrum's events and artifacts. This transparency aligns with the Agile principles that aim to move away from excessive detailed reports. Metrics such as Burndowns, Velocity, Lead Time, and Cycle Time can serve as valuable indicators of the team's progress, work accomplished, and operational efficiency. These metrics primarily empower the team to optimize its processes and enhance collaboration among its members. While these metrics can benefit management, their primary focus is on aiding the team's effectiveness and Agile practices. And the most important question as any kind manager: "How are you doing today ?".