Hi @loerki welcome to the /e/ forum.
From Install /e/OS on a Xiaomi Mi 10 Lite 5G - “monet” we see
Downloads for the monet
- /e/OS Recovery for dev build
- /e/OS build : R dev
the most recently published /e/ ROM is
e-1.4-r-20220923220394-dev-monet.zip
see also e/OS + Android OS version names and numbers?
Android version R = 11 here is the significant thing for you.
The warning is telling you not to make /e/ force a downgrade of Android version (from S = 12). You should search how to downgrade Android version within the Xiaomi environment. Once your device is running Xiaomi Android 11, the install of /e/ will be fine.