My Xbox elite controller is acting like a mouse and keyboard.

Hello Stefanos, this is Manuela. I'm an Independent Advisor and community user like you, ready to assist with this.

Not a Microsoft employee.

It’s unfortunate to know you’re not able to use your controller as expected on your device. Let’s try to sort this out.

However, before that, I would like to ask some questions:

Are you running Windows 10 or 11?
Do you have Steam installed on your PC?
Are you using the controller wired or wirelessly?
What procedures you tried to fix this prior to your post creation and besides updating the controller firmware?

i don't know why having others thins like a keyboard and mouse is cheating if you can used is OK, if you have the elite controller and customized for you're play better is cheating NO. having a keyboard and mouse is another tool

Are you using the keyboard to turn on the console, or a regular controller?

My suggestion is to try using a regular Xbox One Controller (any should do, standard, Elite Series 1 or 2) to turn on the console, launch the game, then turn off the controller, and connect the keyboard and mouse after the controller has been turned off,
you should then be prompted to select an account to use the keyboard and mouse with for the game.

the original Xbox only came with a controller. the Xbox 360 only came with a controller. the Xbox One comes with a controller. you can't buy an Xbox One with a Keyboard and Mouse.
in my opinion if they don't sell them with a Keyboard and Mouse they shouldn't have support for Keyboard and Mouse. if you want to use
Keyboard and Mouse you should play on a PC and not on a console.

Why you say that? telling the mouse and keyboard is taking advantage you can say the Elite control is for advantage too. Only my point of view.