Customizing the visual backdrop during video calls for privacy or presentation
In OBS, choose Tools in the option bar, select VirtualCam, select AutoStart. Then try to restart your Teams. If it is not available, then may be you have to instal OBS VirtualCam AddIn. Using OBS is a very good option to get greenscreen in Teams and others, I have been using it for a year, but remember that OBS will add extra burden to you CPU, so make sure your comp specs are capable of doing it smoothly.
Hope this help.