It sounds like you don’t have any zigbee repeaters other than the hub itself. If so, it’s difficult to evaluate one protocol over the other because you really haven’t set up a working mesh network.
Even when your devices are not very far from the hub, it’s better, particularly in the case of Zigbee, to have at least one repeater because it can just smooth out the working of the network. The hub is almost always busy.
Take a look at the following thread. Start with post 11 in that thread, read that, then go back up to the top and read the whole thing. (The topic title is a clickable link)
In general, a lot depends on the local architecture, as well as the strength of your Wi-Fi system. So one household might find zwave plus works better well another finds that zigbee works better, and a third find they can use both. Sometimes it’s just trial and error.
Definitely if you’re going to be using any battery powered Xioami devices I would recommend getting an IKEA Tradfri pocket socket or bulb to act as a repeater for every four or five battery powered Xioami devices.