Amazon RDS Performance Insights now supports counter metrics on Amazon RDS for SQL Server. With counter metrics, you can customize the RDS Performance Insights dashboard to include up to 10 additional graphs that show a selection from dozens of operating system and database performance metrics. Counter metrics provide additional information that can be correlated with the database load chart to help identify performance issues and analyze performance. 

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/amazon-rds-performance-insights-supports-counter-metrics-on-amazon-rds-for-sql-server/