Adjusting music quality while using Spotify Connect to a digital amp

[Ardbeg996]

Plan

Premium

Country

CanadA

Device

(iPhone 7)/iPad

Operating System

(iOS 13)

My Question or Issue

I wanted to check what quality of music I am streaming at when casting to my nadc338 digital amp via Spotify Connect.  When I listen through my iPhone I can see that they are all set to Extreme -  does this default when I use Spotify connect with the amp?  I can’t change the setting when I am casting to the amp as the option is greyed out and tells me the option is not available when listening on another device.  I am not listening on another device at the time so I am confused.  See attached screen shot. Please help.