Centos8: NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver

You have secure boot enabled so the driver can’t load. Please disable it in bios.
Furthermore, you should rather use a repo driver like rpmfusion so you don’t need to reinstall the driver on kernel updates.
NB: centos has pushed out a broken Xserver update: https://forums.developer.nvidia.com/t/nvidia-linux-x86-64-418-113-wouldnt-build/174775/26?u=generix