HELP: Aggregate device (Overbridge + non-Elektron hardware synths) not working

I’m trying to get DN and DT connected through OB to sync with some non-Elektron hardware to function as a single aggregate device in Mac but it’s not working. I get no signal or sound. I changed the output of my headphone DAC to 48 kHz to match the DN and DT. Still not working. I’m trying to do this so I can multi-track record all my hardware instruments into my DAW: Bitwig Studio. Can someone give me a detailed run down on how to do this? I’ll even pay for a Zoom / Skype session if someone is super knowledgeable of this along with Bitwig. Thanks.