Reports from a few weeks ago claimed that Samsung would finally ditch OLED's made by Samsung Display in favor of ones supplied by Chinese manufacturer BOE. That plan may now be dead in the water, however, as new information claims BOE's OLEDs failed to pass Samsung's quality tests.
https://www.notebookcheck.net/Samsung-Galaxy-S21-now-unlikely-to-use-BOE-OLEDs-due-to-quality-concerns.469511.0.html
I think this was a stunt from samsung to show apple (and others...) that their displays are the best in class. I never believed they would really take displays from another company let alone a chinese one.