I have Home Assistant OS running in a VM on an HP EliteDesk 600 G3 Mini running Proxmox. I don't really use this for automations directly, although I do have some alerts. Primarily I use this as a dashboard and as a common API for everything in the house (zwave, zigbee, hue, Lutron, Shelly, etc).
I honestly don't do a ton of automations. The one really important one controls a hot water recirculating pump with a Shelly One set up as a temperature sensor. This is a small ruby program that uses MQTT to set the state of the zwave switch controlling the pump switch and directly talks to the Shelly for temperature readings. It talks to the HA API for settings but has reasonable fallbacks if things fall over.
I honestly don't do a ton of automations. The one really important one controls a hot water recirculating pump with a Shelly One set up as a temperature sensor. This is a small ruby program that uses MQTT to set the state of the zwave switch controlling the pump switch and directly talks to the Shelly for temperature readings. It talks to the HA API for settings but has reasonable fallbacks if things fall over.