Dell G5 5587 4K Output

Hi,

I am trying to get 4K Resolution Output to my TV via receiver. When I go to Display setting and Multiple Displays set as Duplicates, I am able to set Resolution as 3840 x 2160. But when I set Show Screen only, my Resolution is locked at 1080P.

I want to turn my laptop monitor off while I play games on my TV and be able to get 4K resolution on my TV. How do I resolve this issue?

Thanks,

Daniel