SOS! Buzzing Sound Won't Go Away No Matter What I Do

I started using OBS Studio a while back to stream my DJ sets. I have a DDJ400 and its outputs are 2 RCA cables. I first was sticking this into a TRRS adapter and then into a Lenovo dock I had. It worked in OBS but getting OBS to recognize the dock would sometimes take up to an hour of unplugging and plugging and what not (at first I had buzzing but I swapped out the RCA cables for a new pair and it worked fine). I decided to then get a a dedicated soundcard and opted for the Scarlett Solo. I then tried to take my rca cables, put it into the TRS adapter and plug it into the instrument input on the scarlett. I also alternatively tried to plug my rca's into the TRRS adapter and that into the TRS and that into the soundcard. Both ways it is connected to my computer via USB. Both ways I get a dull buzzing sound when I start streaming. Also, sometimes OBS picks up the audio, or it picks up nothing at all.

FYI, I have muted my computer's internal mic so it's not picking that up.

I clearly have no idea what I'm doing and am exhausted of trying. I've looked over some other answers in the forum, but nothing really solved my problem. Someone please help!!

P.S. I am streaming from a Windows Thinkpad but running rekordbox on my Mac.