Audio Hum from MacMini M2

My Mac Mini (M2) is sending a really loud hum everytime I connect it to my audio interface. I've taken the whole studio down to basics and built it up again (making sure all outlets were grounded, grouping all equipment on the same outlet, adding a power conditioner and DI boxes) and now I find that simply plugging the Mini into the interface causes loud hum. I was using a Focusrite Scarlett that connected with a Thunderbolt adapter and then I tried a newer Focusrite box connecting via USB and they both introduce a loud hum (the USB actually picked up some radio too).

Any idea how to fix this or does it sound like an actual problem with the Mini?