GNU/Linux Debian Bookworm Installing NVIDIA GeForce RTX 4080 Driver Guide
How to Install NVIDIA GeForce RTX 4080 Graphics Driver on Debian Bookworm 12.x desktop – Step by step Tutorial.
The NVIDIA GeForce RTX 4080 Driver Debian Bookworm Setup is a breeze, requiring just a few straightforward shell commands to complete.
Moreover, following the NVIDIA Recommendations is better to use the tested NVIDIA Linux Graphics Driver from the Debian Repository.
Then with the nvidia-settings Tool you can configure Brightness, Gamma, XVideo attributes, Temperature, and OpenGL.
Especially relevant, prior to the Driver Setup you may consult:

GNU/Linux Debian 12 GeForce RTX 4080 Driver Installation Guide