Mono-project template installation?

Got Visual Studio code installed within a template, not connected to the network. However, I’ve hit a stumbling block with getting Mono on the system, securely.

Their installation instructions for Linux based systems requires downloading via:

sudo apt install apt-transport-https dirmngr gnupg ca-certificates
sudo apt-key adv --keyserver hkp:// --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb stable-buster main" | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
sudo apt update

However, this can’t be done without being connected to the internet, they don’t seem to offer a .deb version, only a .pkg (which I believe is Mac). Any ideas what to do here? Compile from source, maybe?

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