OnePlus has just updated a total of 4 flagship variants to OxygenOS 12 based on Android 12. They include the last T-version and the first R-version released by the OEM. The 8- and 9-series units upgrade to features such as an updated UI, an adjustable Dark Mode and their brand's Canvas AoD.
https://www.notebookcheck.net/OnePlus-releases-a-stable-upgrade-to-Android-12-for-the-8-8-Pro-8T-and-9R.609123.0.html