An error occurred while saving the commentsambos commented
@PGone is right, this is an OK workaround for live lectures.
Share your screen (this can be a ppt or onenote presentation for example.) Turn OFF the camera in teams. Share screen, have the presentation open, and then open the Windows camera app, or some other webcam. You can control the size of the camera, and make it small/large at will. I leave it as 1/4 of the screen in the top right. I also use an APP called 'Deskpins' in order to make sure the camera doesn't disappear when I click on the presentation.