The fact is that all Zigbee Coordinator dongles and all Zigbee devices are more or less very sensitive and affected by all types of interference so strongly recommend reading and trying to follow all the various advice here → Zigbee networks: how to guide for avoiding interference and optimize for getting better range + coverage
You also need to understand that Zigbee depends on network mesh technology so it really relies on you adding a few Zigbee Router devices that will act as Zigbee repeaters to extend range and coverage as well as add stability to the Zigbee network if and when the Zigbee Coordinator goes down.
If possible you should not have any Zigbee End devices (battery-powered devices) connected directly to the Zigbee Coordinator, instead, they should preferably connect indirectly via known good Zigbee Router device(s) that is located closest to that Zigbee End device (battery-powered device).