EDIT solution: The problem was that I thought the package installs the driver but it was not the case (more about it in the accepted answer). When installing Nvidia driver I suggest going with .run file from archive here - if you need specific version, which was my case so I could not just autoinstall. The .deb package was not working for me.
EDIT2: I tried to install Cuda just now and failed. I've read there might be issues when using ".run" file, so I don't know if that is the way to go anymore.
I have Debian 10 (Buster) and I'm trying to install Nvidia driver 460.91. I downloaded it and tried to install as root by executing:
apt install ./<name>.deb
What I get is: https://i.imgur.com/FeErHh5.png
and the driver is not installed.
Why the Nvidia driver is not installed when it is claiming that the package is? Also the first run was extremely fast so it could not possibly install the driver.
I tried among other things running
sudo dpkg -i <name>.deb sudo apt install -f
but got same result. For some reason it seems that the package is installed however the driver is not.