First thing on screen after factory reset is lack of mouse connection

I recently did a factory reset on my iMac. Following this the unit was turned off prior to going through with any of the initial set-up (I believe Mojave OS). For clarification I didn’t select location, language, etc., literally powered down after the reset was complete. The next time the unit was powered on, the screen provided the animation for pairing the Bluetooth mouse, and that’s it. No ability to use the mouse, keyboard, or track pad. All have new batteries in them. In essence there’s nothing I can do to move past this point and get to the point where I can go through the initial set-up. I turned the unit off and then repowered, but had the same results. At this time the unit is rendered useless. Any recommendations with a procedure to get through this is appreciated.