Ubuntu versions prior to 24.10 do not have .NET 9 in their standard repositories. To install ssprea-nvidia-control on these versions, you need to add the Canonical PPA for backports:
sudo add-apt-repository ppa:dotnet/backports
sudo apt update
More details about this PPA can be found here.
Copy and paste the following commands in your terminal:
curl -s --compressed "https://ssprea.github.io/snvctl-apt-repo/ubuntu/KEY.gpg" | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/snvctl-apt-repo.gpg >/dev/null
sudo curl -s --compressed -o /etc/apt/sources.list.d/snvctl.list "https://ssprea.github.io/snvctl-apt-repo/ubuntu/snvctl.list"
sudo apt update
sudo apt install ssprea-nvidia-control ssprea-nvidia-control-cli
NOTE: CLI package is required for GUI to work properly.
If you get an error that looks like this, follow the backports PPA section:
The following packages have unmet dependencies:
ssprea-nvidia-control : Depends: dotnet-runtime-9.0 but it is not installable
ssprea-nvidia-control-cli : Depends: dotnet-runtime-9.0 but it is not installable
E: Unable to correct problems, you have held broken packages.