Set the Core Debug Level to Verbose and see what is logged to the terminal. This may indicate why the Core 0 is panic’ed.
For the Switch:
ZCZR 4Mb with Spiffs
ZCZR Coordinator or Router.
For the Light:
4Mb with Spiffs
Zigbee ED (end device).
Program both.
Start the Switch first. Then within 180 seconds, start the Light.
If for some reason the light has already joined a network, reset to factory settings by holding the Boot button for 5 seconds.
Then reset the Switch and the Light should join and bind.
Each (Boot) button press on the switch should flash the RGB led on the Light when the light is turned on, and do nothing when turned off.