Maybe try turning off loopback if you don’t need it. This will hopefully stop the feedback.
Loopback is generally for podcasting where you have to record yourself speaking over the audio out of the computer. Generally you would use headphones while recording to avoid any feedback from speakers.
I contacted support about the loopback question I had and they said it’s designed this way to avoid accidental feedback. So in order to record the mic with loopback you have to turn the mix knob to the center.