W-LAN

In the most used switches in my house I have shelly 1 or shelly 2.5 integrated. The switch switches the shelly and the shelly switches a relay which lets the power be on or off. In parallel I can switch the shelly over W-Lan. The shellies are connected to shelly-cloud, which is connected to alexa. The home assistant includes the shellies with shelly for hass integration.

Zigbee protocol

It's standardized. But each brand uses it's own implementation of the standard. The advantage is low power consumption and each node with power, not battery, works as a repeater in the mesh.

Philipps Hue lights are working with Hue bridge, the bridge will be found by home assistant automatically. I'm using the bridge with alexa to switch lights on and off.

For window sensors I wanted to use aqara sensors. But I didn't want to use a chinese cloud. Therefore I bought a ConBee II stick to have an integration into home assistant.

For this you need two parts. One is the integration which connects home assistant to a software which is using the ConBee stick to connect to the zigbee devices. This second part is easiest running as an addon to home assistant. To use an addon of home assistant you have to have a supervisor. That means you have to install home assistant with its OS and not as part of kubernetes. I had a sparse raspi II and installed it with its image on a 32GB card. 27 minutes later it was identified as homeassistant in my network.