Xiaomi Mi 9T / Redmi K20: here is Android 11 with custom ROMs
Xiaomi Mi 9T Pro nadograđen na MIUI 12.5 i Android 11 - Bajtbox
Install Android 11 on Xiaomi Mi 9T (LineageOS 18.1) - How to Guide! - YouTube
New Xiaomi Android 11 update list shifts remaining confirmed devices such as the Mi 9 series, Xiaomi Black Shark smartphones, and the Mi A3 to internal testing status - NotebookCheck.net News
Update: Russia] Android 11-based August 2021 security update releasing for Xiaomi Mi 9T - RPRNA
Download China Stable Android 10 MIUI 11 For MI 9T Pro (China Only)
Xiaomi Mi 9T ROM Download: latest update MIUI 12, Android 11