Try to follow this as best you can → https://community.home-assistant.io/t/guide-for-zigbee-interference-avoidance-and-network-range-coverage-optimization/515752
Also see → https://www.home-assistant.io/integrations/zha#defining-zigbee-channel-to-use
As well as follow this too → https://www.home-assistant.io/integrations/zha#best-practices-to-avoid-pairingconnection-difficulties