iPhone 8 Plus. What is this circled connector for? My Wifi is greyed out and is not working, is it because it's broken?

[iMAK79]

 

[chabig]

I know a little bit about electronics and I don't even see a connector inside your circle. But maybe go watch iFixit teardown of an 8 Plus. You might find an answer there.

 

[iMAK79]

I know a little bit about electronics and I don't even see a connector inside your circle. But maybe go watch iFixit teardown of an 8 Plus. You might find an answer there.

You see the two screws inside the red circle, they are holding holding a connector.

 

[chabig]

Maybe a different angle would show it better.

 

[wilberforce]

Monopole antennas need a ground plane (A dipole or loop antenna doesn't). The phone body may be acting as a ground plane.
Or different parts of the phone body, separated by insulators (the white plastic lines), may be acting as the antenna(s).