Xiaomi brought the Redmi K20 in 2019, Redmi K20 is known as Mi 9T in China. It has specifications like Snapdragon 730, 6/8 GB of RAM, a 4,000 mAh battery, a 6.39-inch display, and it has up to 256 GB of onboard storage.
It has a triple camera setup with a 48 MP primary shooter. In the front, a user will get a pop-up style 20 MP selfie camera. Redmi K20 also has an under-display fingerprint scanner.
The device came with Android 9 Pie, but, according to reports, in January, Redmi K20 got the Android 10 update in India but, the global variant got the update in February.
Users who want to install LineageOS in their Redmi K20 aka Mi 9T, then they can install LineageOS 17.1 as it is now available with Android 10 support.
The Mi 9T users can have the official LineageOS 17.1 (Android 10) support with the regular OTA updates.
LineageOS is the most popular custom ROMs, which is known to any Android user who is a fan of improving and modifying. Users can install the LineageOS without installing any Google application.
As per abhishek987, XDA Senior Member, a user can install the unofficial LineageOS 17.1 for the Redmi K20 / Mi 9T. Many devices have access to the unofficial LineageOS 17.1 updates.
A user can download and install the unofficial versions on different devices. There is no issue reported till yet.
How To Install LineageOS 17.1 on Redmi K20 / Mi 9T?
However, the unofficial version of the LineageOS does not give a guarantee of OTA software updates daily. The update is available on official versions so better to download from the official version.