Not sure whether the problem is caused by interference, the mesh, the coordinator or a single device?
I can remotely review the ZHA or Zigbee2MQTT configuration, logs, network map and the available information about link quality and device behaviour.
I will not guess at factors that cannot be assessed reliably from Home Assistant alone, such as the physical placement of the coordinator, local radio interference or power quality. If needed, I will suggest a simple test or measurement that can be carried out on site.
The analysis will help narrow down the likely cause, avoid random changes and define the next steps. If the issue is a weak, faulty or incompatible device, I will say clearly whether replacing it is the more sensible option.