With this app you can have notifications shown for all MIUI devices:
You just have to give all the permission asked then set the x and y padding accordingly to your phone.

Tested on:
-Pocophone f1
-Xiaomi mi8 lite
-Xiaomi mi9
-Xiaomi mi max 3
- Xiaomi mi8
- Xiaomi redmi note 5 pro
- Xiaomi redmi note 6 pro
and many others