Using the Home Assistant native built-in ZHA integration as Zigbee gateway solution or a third-party like Zigbee2MQTT or other Zigbee gateway application?
Regardless, while not always the most common and often seen root cause of such problem symptoms is either EMF/EMI/RMI interference or not having enough “good” Zigbee Router devices, alternatively a combination of those two, see → Zigbee networks: how to guide for avoiding interference + optimizing using Zigbee Router devices (repeaters/extenders) to get best possible range and coverage
Also note that there are two different Sonoff Zigbee dongle models based on different radio chips (ZBDongle-E and ZBDongle-P), which one do you have and what firmware version using today? → Zigbee buyer's guide