Security system problem, no electrical power anywhere

When you say the vehicle has no electrical power anywhere, do you mean the battery is drained or the vehicle will not start due to the security system? Is the theft light remaining on? I assume you have a push button start so what happens when you press the button with the key in the vehicle? Do you have any message in the cluster when you press the button?

Can you push the button with the key and see if this causes it to start?

Maybe get a video of what happens when you try to start the vehicle. Thanks