Terragen 4.5 is built with a much newer version of Visual C++ than Terragen 4.4, and it uses different dependencies from 4.4, so this is normal. If you want to use Terragen 4.5 please let the installer download the dependencies it needs, or - since you are on an airgapped system - you can download the dependencies yourself and install them before installing Terragen.
The Terragen 4.5 installer may want to install two sets of Visual C++ Redistributables: 2010 and 2015-2019. Make sure you get the x64 versions if you are downloading them yourself from Microsoft.
I see that you have some version of the 2015-2019 redistributables installed, but there are multiple possible reasons why this isn't sufficient. It may be an earlier version than the Terragen installer requires (14.24.28127), or it may have been installed in a way that the Terragen installer doesn't detect. There is more than one way for the installer to detect this, and unfortunately neither method works 100% on every computer. Therefore in some cases the installer will want to download dependencies even if you think it shouldn't need to.