The http://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64 NVIDIA repo is probably what’s causing the problem.
You can run grep -r developer.download.nvidia.com /etc/apt/sources.list.d to find the APT list that contains the NVIDIA repo. Delete the list.
Run sudo apt update &> nvidia-smi-troubleshooting.txt again so we can see the new output.
(Also, you might want to comment out line 57 of /etc/apt/sources.list to suppress all the […] is configured multiple times in /etc/apt/sources.list:57 and /etc/apt/sources.list.d/lambda-repository.list:1 warnings you’re receiving.)