The Galaxy S10s are Samsung's first flagships in which the front-facing cameras peek right through their high-end OLED displays. However, their future replacements may not even require the cut-out in order to fit around a camera. These panels may provide a full-screen experience by hiding all their sensors underneath them.
https://www.notebookcheck.net/Samsung-s-next-generation-displays-are-set-to-engulf-and-hide-cameras-completely.414571.0.html
2 more years... so 4 more for apple ;D
It's a significant distance away. It requires all layers of the screen to be incorporated into the optical design, much more complex than a mere glass filter.