How to track KPI

Hi Jira Support,
We are currently using Jira for a software project, and our project is set up as a team-managed project. We already have the story points field set up in our issues, and we have two employees. We want to implement a KPI system to reward them based on their story points, sprint completion, and bonus KPIs for extra work done.

Could you advise on the most efficient way to track and monitor story points and sprint completion percentages, especially when the issues vary in complexity? Additionally, how can we handle bonus points for tasks that exceed the initial scope of a sprint? We are looking for best practices or Jira features that can help us automate and streamline this process for maximum efficiency. Thank you!