Reddit reviews Multi-purpose USB Isolator (Built-in DC-DC)

As someone who also has this issue (at random intervals, also only while talking, and while using a Blue Yeti) I believe the USB theory is not necessarily a single port problem but more of a problem with how your whole system delivers power to the ports, so swapping ports or changing cables would not make a difference. Removing all other devices powered by USB connections might, if you have any plugged in. As /u/EternalConflict suggested, you could try a wall-powered USB hub (I have not tried this) or there are also devices for "cleaning" the USB power (which I have also not tried) but both are going to require you to price your faith at $20-$40.

What you can do in the meantime is try to find a couple small sections of that buzzy sound (try zooming in and testing right before the start of your words), copy/paste it into a new Audacity file, then use that new file to get your noise removal sample. (I hope I'm making sense.) Usually, if I do that with the sensitivity somewhere around 4, it's good enough to get most of that junk out in one pass without ruining the file. For me, though, anything over 5.5 on the sensitivity generally starts flattening out my voice at a really noticeable level.

Good luck -- I know from experience that this is a really frustrating issue, so I hope you're able to find something that works for you.