According to a report, Xiaomi has over 60 devices in closed and internal Android 12 beta programs. Numerous other devices will eventually receive Google's latest OS, but not older handsets like the Mi 9, Redmi K20 or Redmi 9 series.
https://www.notebookcheck.net/Xiaomi-is-testing-Android-12-on-over-60-devices-in-closed-and-internal-betas.576864.0.html