OnePlus has finalised some of the changes that it will be adding to OxygenOS. The new features have been whittled to seven from thousands of community suggestions, and include a proper dark mode, not a dark grey mode as is currently available on OxygenOS 11.
https://www.notebookcheck.net/OnePlus-announces-seven-new-features-that-will-be-making-their-way-to-OxygenOS.505092.0.html