This is a problem with a Dell utility, not a Microsoft problem. I had the same problem with my LG laptop. All you have to do is search Google for "Dell Win11 noise suppression." This is what I found:
https://www.dell.com/community/Inspiron/How-to-disable-background-noise-suppression-for-the-microphone/td-p/8310256 I'm guessing this is the MaxxAudio Pro software's Noise Guard feature. You can turn it off in MaxxAudio Pro's Advanced Options: un-check the box for "Activate Noise Guard".
AFTER you turn off the Dell noise suppression, you need to change the audio setting in Zoom to "low" noise suppression. This is what I use for my violin lessons on Zoom and it allows the microphone to pick up the violin. But then I have to change back to "automatic" for my other Zoom meetings or everyone can hear the baby birds crying for food in the tree outside my window.