Have you enabled the Virtual Backgorund option just like this guide
told:
https://support.zoom.us/hc/en-us/articles/210707503-Getting-started-with-Virtual-Background#h_2ef28080-fce9-4ac2-b567-dc958afab1b7
Agree with acompton, Zoom supports removing background without a green
screen. Just unselect the option 'I have a green screen'.After that, you
can upload an image to be your background, or you can choose to download
an app named Virtual Backgrounds,...