Is there an easy way to do that?
It should cover zwave, template sensors, custom components etc.
If something goes unknown, none or didn‘t update for x hours a message with a summary should be sent. This check can slo be done every minute.
I know I can add all entities manually, but there are so many.
Also what states of failure should I monitor? (Unknown, none, last_updated)
Is there more?
Maybe THIS is the one for you.
and here is another solution
dummylabs/thewatchman: Home Assistant custom integration to keep track of missing entities and services in your config files (github.com)
This looks very interesting. It’s probably also a good idea to use to check automations.
In addition to my script to check for last_update of battery powered devices being greater than x hours I should be able to cover most failures.
They are similar but also different… The batteries part is your data…the other is quality of managing functionality for your data (system)…they both work independently but they both provide you a view of the overall quality 