Question about Proper Use of Advertising

[Shavell]

Hello, I have a "LYWSD03MMC B1.6, Software Version: 4.6" device and I am working on a project. I thought you could help me choose the right technology. I will be using either Zigbee or BLE. As far as I can see, BLE requires an active connection and does not work in a fire-and-forget manner. For Zigbee, I think it does not require a mutual connection. Which one should I use for optimal battery performance? Thank you.