I’ve been having issues with latency, availability and stability across my zigbee devices. This has meant automations not triggering or partially working and a significant amount of frustration, never mind negative values on the WAF scale.
Whilst not all resolved yet some of its information has definitely helped improving things.
Hope others find it useful.
https://docs.hubitat.com/index.php?title=How_to_Build_a_Solid_Zigbee_Mesh