gcc-12 is not installed by default in Zorin OS 17, but it is available in the repositories. You can install it with:
sudo apt install gcc-12
But this is likely not enough, as it's still hard-coded to use the version prior. To use it, you need to update the symlinks with the following commands:
sudo rm /usr/bin/gcc
sudo ln -s /usr/bin/gcc-12 /usr/bin/gcc
I suggest to revert this back the way it was when you're done. I'm not sure if it actually makes any difference, but just in case:
sudo rm /usr/bin/gcc
sudo ln -s /usr/bin/gcc-11 /usr/bin/gcc