Zoom does not recognize a webcam over a Citrix connection to the Virtual Machine.
Uninstall any Zoom software on the Virtual Machine.
The VDA on the Virtual Machine should be Citrix Apps & Desktops 1912 (our latest DesktopConfig), because the prior supported configuration doesn't support 64-bit applications using webcams. The Citrix Workspace App on the local PC workstation should be the latest Citrix Workspace App, as Citrix Receiver does not support 64-bit applications using webcams. Zoom is a 64-bit application.
Citrix Published Desktops on CloudConnect