I might experience similar thing with Mcfarlap. Since using macOS Ventura, zoom always cuts off background noise. Idk, it understands human's voice like mine, but it can't understand a non-human voice like guitar voice, or clapping hands, or even when i hit the table it all can not be catch by zoom.

It still can't when the BG noise suppression is set to low. And when i change into original sound "off" and "on" it still the same.
Both with professional mic with audio interface, USB Mic, or even with no mic at all (mic from the mac itself), zoom still cuts off background noise.

The strange thing is, when i use gmeet, it's all fine, working properly.

And i tested zoom in my friend's macbook air M1 with macOS Monterey, and it's working fine. So im suspicious that this is because of the bug caused by macOS Ventura in my macbook.

After I re-install macOS with monterey, zoom works fine. Now it can understand non human voice like music instruments.