A consultant at DSCC claimed that the Samsung Galaxy S21 will not be featuring an under-display camera, likely due to poor yields and possible compromises in terms of image quality. This could upset hopes of an "all display" Samsung flagship this year.
https://www.notebookcheck.net/The-Samsung-Galaxy-S21-might-disappoint-with-no-under-display-camera-says-display-supply-chain-analyst.484222.0.html