Have you played around with Grafana? It really is quite simple if you have prometheus already working.
For a home lab environment you dont even need to use prometheus-alertmanager. Grafana can handle alerts as well.
Grafana also has hundreds of pre-made dashboards you can import. Node monitoring is quite straightforward.
Assuming you have prometheus good to go, all you need to do is go to Grafana - Datasources, create a new datasource, point to your prometheus instance.
Then you can import the dashboards you want.
Now you can setup your alerts - you can use SMTP, telegram, slack among others for your notifications.