When using my Universal Audio Apollo, the audio always plays out of my iMac speakers

I have been using my Universal Audio Apollo 16 on an imac for a few years now but recently my old iMac died and I got a newer one. I got a thunderbolt 2 to thunderbolt 3 adapter and downloaded the most recent Universal Audio software and drivers. The interface is recognized by my OS and I can choose the interface as the output for my OS. This works fine and I haven't had any problems getting my computer audio routed through my Apollo 16 when I set it as my system audio output.

However when I set the Logic Pro input and output to the Universal Audio Apollo, it will output through my iMac speakers. I've tried restarting multiple times, reinstalling the UA drivers, quitting logic, restarting the interface, and trying again, and nothing has worked thus far. I've also tried disabling and re-enabling coreaudio, and restarting logic.

I have also tried using a usb headset as the input and output in Logic and I have the same problem. The main stereo out in Logic comes through my iMac speakers. If I set my output to external headphones with headphones plugged into the iMac, the sound still comes out of the iMac speakers. I have tried messing with the routing a bit in Logic and still have no luck.

Any idea why this is happening? Thank you!