Xbox Change input to mouse and keyboard

Hi all, I have connected a Bluetooth mouse and keyboard set to my Xbox Series S. I am able to navigate the menu in AoE II DE, however in game I find the mouse unresponsive. When I go to Options → Interface → Input it tells me “Input: Controller (This option cannot be changed in-game)”. I cannot switch to mouse and keyboard, the ‘Controller’ line is greyed out. However I am not even in-game, I just launched AoE II DE and then went straight to the Settings, there is no game running. So how can I change from Controller to Mouse and keyboard?