controller sync

Sync the Controller:
To sync a wireless controller with your Xbox, follow these steps:

Press the Xbox button on the controller to turn it on.
Press and hold the small sync button on the front of the Xbox Series X console (located near the USB port).
While holding the sync button on the console, press and hold the sync button on the controller (located on the top near the Xbox button).
Release both sync buttons when the controller's Xbox button starts flashing. The controller should now be synced with the console.

You have to sync your second controller, via the Xbox One's sync button on the left, and the controller's sync button on the top.

Hi, you are pressing the sync button on the console and then the sync button on the controller? What happens when you try to sync the controller?

Try re-syncing the controller to see if that helps.

Press the sync button on the front of the controller and the sync button on the console to see if it will reconnect.

Have you tried syncing the controller to the console? Hold the sync button on the front of the controller and the sync button on the console (on the left side just before the usb) until the light on the controller syncs.

If that doesn't work then try heading over to Settings>System and update the controller to see if that helps.