Which RHEL metrics are recommended to monitor?

Issue

• There is a demand to improve the monitoring of the Linux environment. The idea is to get all the counters/outputs that would be interesting to be collected for monitoring and troubleshoot in the Linux operating system.
• There is no sticking to specific monitoring tools or setting thresholds. At this stage, it is just a collection and definition of which indicators are interesting, and for what reasons.
• Does Red Hat has a documentation/guide/recommended practices/manual or any other document related to this topic that can help?