I am struggling with the same question. (Wifi (Tasmota) / Z-Wave / Zigbee / ikea trådfri / KNX ??). I am currently using Wifi / Tasmota and Z-wave for more than 3 years. Both work well. What I don’t like about Wifi is the usage of a existing infrastructure which is also used for many other data traffic. Z-wave seems most secure, most reliable however relative expensive. This article might help: https://thesmartcave.com/z-wave-vs-zigbee-home-automation/