Hi. I'm David, and I'm happy to help you.
I suggest installing the latest graphics driver provided by Lenovo for your laptop.
Download the driver from the link below:
Driver name: VGA Driver for Windows 11 (64-bit) -V14 G2 IJL, V15 G2 IJL
Version: Intel_VGA_31.0.101.2130_4ID_WHQL_241028
(Run the downloaded EXE file and follow the on-screen instructions to install the driver.)
After installing the driver, restart your laptop and see if you can adjust the brightness.
If the problem persists, please let me know.
Feel free to ask back any questions.
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