The OBS virtual webcam device doesn’t always get removed properly when OBS studion is removed on Mac. Here’s how to manually remove the device.
Using finder navigate to “/Library/CoreMediaIO/Plug-Ins/DAL/”.
Command + Shift + gwill bring up the goto dialog.
Delete the “obs-mac-virtualcam.plugin” file.

Verify if the “obs-virtual-camera” device has been removed. The screenshot below is from MS Teams.
