I’ve had issues with Zigbee interference for a long time, though never had an issue with Z-Wave. I’ve also been fighting constant interference with my TCP bulbs. At this point my bulbs are useless as they are pretty much always disconnected (along with my original SmartThings motion and multi sensors). I’m curious to know how everyone has hubs, routers, and such setup in their homes to help avoid this problem.
I have my router broadcasting 2.5 (ch. 11) and 5GHz. My SmartThings hub is connected to it and sits below and a couple of feet to the left. The TCP hub is slightly above the router and another foot or so to the left of the ST hub.