It's not, you can do that under the video settings if you hover over the camera icon on the calling screen, or there's a device settings buried under the overflow menu as well. Haven't used Teams in a while, but I doubt it changed now.
"Spotify already pays nearly 70% of every dollar it generates from music to the record labels and publishers", yet musicians still get paid incredibly bad. Maybe if the only way of making your business model sustainable is by underpaying artists, your business is just not sustainable.