To save you going 5 min into the video.. He was using an adapter with zigbee2mqtt that was listed as experimental.
It is less about the network adaptor and more that ~~he switches from zha to zigbee2mqtt with~~ the skyconnect / homeassistant adaptor that is still not fully supported in zigbee2mqtt.
Using a coordinator more central to your network can help but as long as a large number of your powered relay devices have a strong connection there isn't anything wrong with using the USB ones.
The ONLY issue with the USB ones is that it is recommended you put them on an extension cable as the USB port it self can cause interference, and putting a little distance from the antenna helps.
So his solution DOES all that, and is a good solution, but I wouldn't just go toss your USB stick in the bin..