+1 for CMK. It’s built on nagios. Been using it for decades. That shit is rock solid and has never let me down.
Prometheus is metrics and grafana reports it. IMHO, better reporting and graphing, better eye candy. But also harder to setup and get right.
CMK agent works on 95% of what you want with just the agent.
PopOS I have to be at the bar and I will have a little early and then I’ll get you some food for the day off the road to get the title and I can come by.