Network-connected devices (Rokus, computers, whatever) have no innate IP numbers of their own. The number is assigned by the router each time it connects to the device. Until it is connected to a network a Roku doesn't have an IP number.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X