Hi RevdLaurie,
Thank you for reaching out Microsoft Community. We apologize for the inconvenience this has caused you.
To initially troubleshoot this issue, I'd like you to run the system file checker to see if this issue is due to corrupted system files. To run the system file checker, kindly type Command Promp****t on the search box next to the Windows icon and run it as administrator. Once done, type and enter sfc /scannow. Let it load, detect and repair those corrupted files. If it didn't detect any corrupted files, please restart your Surface device and please run the Surface Diagnostic Toolkit.
After running SDT, you can uninstall/reinstall the Zoom app. Then, open Device Manager. Expand Audio Input and Output, right-click on each driver and select "uninstall device". Once done, re-download the drivers from this link>>https://www.microsoft.com/en-us/download/details.aspx?id=56261. Choose the first msi file and download it completely.
If this helps, feel free to mark this post as an answer. Otherwise, don't hesitate to respond to this thread if you need further assistance.
Kind Regards,
Crest_Z