Hi, sorry for the issue. please refer to NSPanel Pro V4.0.12 impossible to complete update - #3 by MichaelLearnsToCode for how to clear the cache of NSPanelPro App.
Or you can click Check button on the alert and use password smatek@123 to manage the storage. You can safely delete files from /data/data/com.eWeLinkControlPanel/files/ota/.
PS: As a last resort, you can always do a Factory Reset. The cost is a bit high. You will need to do all the configurations again, including re-pairing Zigbee devices.