-switching from a Hat coordinator to a CC2652P USB one with an extension cable
-choosing different Zigbee channels that were unlikely to overlap with Wifi ones
-using “stronger” routing devices (more expensive brands like Innr)
What happens is that eg when I toggle a group of lights via the HA interface, oftentimes a few of them won’t react. This usually happens when I toggle them twice within a few seconds.
This may be the problem. Messages to individual Zigbee devices take the most efficient route; messages to Zigbee groups are blasted out to every node in the network, just to make sure that every member of the group gets them. If you send several in succession it can swamp the whole network.