My setup is pretty much all Zigbee (100+ Zigbee devices versus ~6 Z-Wave devices), I can tell you first hand that channel 25 for Zigbee is a bad idea. The lower you can go in Zigbee channel selection and the higher you can go in Wifi 2.4ghz channel selection, the better off you will be. I currently have my WiFi 2.4ghz channel set to 11 and my HE Zigbee channel set to 14. My Hue hub, also Zigbee, is on channel 20. My farthest run device is a bulb that is 75' from my HE hub through 2 interior walls and 1 exterior wall. I have two smart plugs acting as repeaters in between the bulb and the hub and that bulb responds quickly and without fail.
One thing I will add is that Zigbee is a protocol that takes patience. The more devices you have, the longer it takes the mesh and routes to heal. So, when you change the Zigbee channel on your hub, bank on waiting about 12-24 hours (for a small amount of devices) before really testing. On my network, it typically takes ~36-48 hours for my mesh to fully heal when adding, deleting, or moving devices.
Just something to keep in mind.
