Here are some other random configs I've made that aren't in my ESPHome repo - stuff for Home Assistant, Genmon, etc.
First, you obviously need to enable MQTT within Genmon and Home Assistant. Then, to prevent "Unknown" statuses, set the Flush Interval to 300 seconds in Genmon.
After you do that, you can either copy and paste the config directly into your configuration.yaml, or you can copy the entire file itself next to the configuration.yaml file and simply add
homeassistant:
packages:
genmon_ha: !include genmon_ha.yaml
to your configuration.yaml.