How can I add a new audio device when it doesn't appear under Preferences?

Going to Preferences>Play>Audio Device Setup, the new device (Schiit Modi DAC to Cambridge amp to ELAC speakers) does not appear under ASIO Driver, and I get no sound. This was not an issue with my prior audio device (Focusrite to headphones). I’ve tried restarting/unplugging and replugging the new device.

You might need to install a driver or smth?

If the device is itself not an ASIO-compatible device, then it won’t show up itself in Device Setup. Instead you will need to choose the Generic Low Latency ASIO Driver or ASIO4ALL and then configure that driver to use your new device.