How to make CUDA 11.3 work with Blender 2.92 ? (Debian 10 Buster / Nvidia GPU)

Hello everyone,

On Blender 2.92, I'm trying to use Cycles renderer with a Nvidia GPU (Quadro P400)- my operating system is Debian 10 (Buster).

To install CUDA, I read NVIDIA CUDA Installation Guide for Linux (https://docs.nvidia.com/cuda/cuda-installation-guide-linux/index.html#introduction) using the following commands :
1) Uninstall nvidia-cuda-toolkit and it's dependencies -> apt-get remove --auto-remove nvidia-cuda-toolkit ;
2) Download installer -> wget https://developer.download.nvidia.com/compute/cuda/11.3.0/local_installers/cuda-repo-debian10-11-3-local_11.3.0-465.19.01-1_amd64.deb ;
3) Install repository meta-data -> dpkg -i cuda-repo-debian10-11-1-local_11.1.0-455.23.05-1_amd64.deb ;
4) Installing the CUDA public GPG key (local repo) -> apt-key add /var/cuda-repo-debian10-11-3-local/7fa2af80.pub ;
5) Enable the contrib repository -> add-apt-repository contrib (NB: was already done) ;
6) Update the Apt repository cache -> apt-get update ;
7) Install CUDA -> apt-get -y install cuda
8) reboot .

With nvidia-smi command I get :

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 465.19.01 Driver Version: 465.19.01 CUDA Version: 11.3 |
|-------------------------------+----------------------+----------------------+

Strange thing: at this moment the Blender software does not open anymore, I have to reinstall it to open it again. With Flatpak I do :
1) Uninstall Blender -> flatpak --system uninstall blender ;
2) Install Blender 2.92 -> flatpak install flathub org.blender.Blender .

Blender opens again after reinstallation. Then when I go under Edit -> Preferences -> System -> CUDA, an error message says "No compatible GPUs found for path tracing Cycles will render on the CPU" as if I had not installed any drivers or CUDA Toolkit.

I'm running out of ideas to solve my problem. Maybe someone has a clue?