Unable to set External Display Resolution

Hi all, i am wondering if anyone has issue with displaying to external monitor or tv? 

i am using Jsaux HB1201 dock, connected to my sony KD85x85J TV via hdmi 2.1 cable. 

First i am unable to get 120hz despite my tv supported it.

2nd if i set tv settings to VRR, it will display sideways.

3rd  when connected to TV, despite it being a 4k TV, and in display settings it says signal 3840 x 2160, but it says desktop mode 1920x1200. launched legion space to change to 2560x1600. but still the same. display settings resolution all greyed out once i set to display to tv only. 

How can i manually set the resolution to the correct one, and also the aspect ratio? my tv is 16:9. but it dsiplayed as 16:10. Black box on both left and right. 

Hope someone can help me out. i bought this mainly to use as a desktop daily work too. apart from light gaming.