Hi,
I am using Zigbee2mqtt running on docker on raspberry pi for couple of months. Initially I was using raspberry pi zero with Sonoff Zigbee USB Stick. Everything seems to be working fine except that from time to time the Zigbee devices connecting thought Zigbee2mqtt going unavailable at the same time. Most of the time a restart to Zigbee2mqtt would resolve the issue. I switched to Raspberry pi 4B to make sure it is not a hardware issue, still I am having the same issue only not as frequent. At random time the devices becomes unavailable.
I switched debug logging on in Zigbee2mqtt I cannot see anything special. Only MQTT messages received.