grozier: what switchback bulbs are you using? And are your DRLs set to "Parking Lights as DRL" and they operate as white? The switchback LED bulbs I have will only illuminate amber in DRL mode, so I'm curious if another brand might work. They DO illuminate white in normal operation (ie, as marker/parking lights with the lights fully on), and switch to amber for turn signals.
The bulbs I have were purchased originally for my F150- they're "ClaraLux CL65" 3157 bulbs. Can you give the part info you're using if they're operating as White DRL?
One thing I HAVE NOT tried is to enable/disable the DRLs via the 8.4 screen, though I do have the option enabled via AlfaOBD. All I know is that they operate in whichever location I've enabled in AlfaOBD (currently set to my Fog light location).