Do not get to the GUI login screen after installing NVIDIA CUDA 11.4 driver on RHEL 8.4

I installed the NVIDIA CUDA 11.4 driver on a computer with RHEL 8.4…

Now after GRUB starts, the computer does not get to the GUI login screen.

How can I debug and fix this, as it is delaying a critical project?

A day ago I installed 64-bit RHEL 8.4 on the same computer, and was able to get to the GUI login screen, as well as
to log in as root or an user into the GUI environment.

After installing CUDA 11.4, I set the $PATH variable to include /usr/local/cuda-11.4/bin

and the $LD_LIBRARY_PATH variable to include /usr/local/cuda-11.4/lib64

as the computer is 64-bit.

lspci | grep -i vga
lists the GPU card that I have installed,
and nvidia-smi
shows that the CUDA driver is installed.

How to debug this, so that I can hopefully get it to work today?

Thank you very much!