Suggest first try both upgrading to very latest community build for your specific Zigbee Coordinator adapter, (noting that there are “Sonoff ZBDongle-E” and “Sonoff ZBDongle-P” models that use different radio SoC chips so have different firmware), plus also follow all the best practice tips here → Zigbee networks: how to guide for avoiding interference + optimizing using Zigbee Router devices (repeaters/extenders) to get best possible range and coverage