Ubuntu + cuda version issue

My system is a Dell Laptop + A5000 GPU, with Ubuntu 2004.
Late last week my GPU became “invisible”, i.e. nvidia-smi could not contact the GPU. Tried to reinstall the driver. Still broken.
Then I removed the nvidia-cuda-toolkit to reinstall cuda from scratch. I also did the auto-remove.
I then went through the steps at the bottom of this page: CUDA Toolkit 12.2 Update 2 Downloads | NVIDIA Developer

The install fails on the last step:

harald@harald-Precision-7560:~$ sudo apt-get -y install cuda
Reading package lists… Done
Building dependency tree
Reading state information… Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
cuda : Depends: cuda-12-2 (>= 12.2.2) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
harald@harald-Precision-7560:~$

Questions:
Does this indicate that the latest (12.2.2) toolkit is not supported on Ubuntu 2004? If so, which toolkit version to use?
If a “component issue” that can be fixed, how can I determine what might be broken and what I need to purge/re-install? I would hate to have to reinstall Ubuntu++
.
Harald