Grafana and Prometheus are great if you have numeric things you want to monitor. CPU usage, RAM, disks, throughput, etc. You can then do lots of things with these numbers, mainly compare them to your other systems or alert when they go out of bounds.
However, I very much prefer Zabbix for my home network monitoring as this is not so fixated on numbers but can easily work with e.g. error messages in logfiles and alert on those. Or I can regularly check a website for new firmware versions and alert once the latest version changes. There are also lots of ready-to-use templates available from their Community Hub.