Thank you very much 
I have found the solution. There's none 
After I installed windows, it didn't work either so I look up on dell's site and have found a bunch of users very angry because dell just decided to limit the resolution output to 1920x1080 in a lot of their notebooks. So no matter if the gpu supports it, they block it 
Resolution on external monitor limited to 1920 x 1080 using HDMI | Dell US
Thank you anyways 
You're awesome.
Also, if you don't mind, can you tell me how to revert to the previous kernel and remove OEM kernel? 