Perhaps it would be better and easier to build a virtual machine, take a snapshot with all the programs and configurations you need, and run that in your air-gapped computer. That way you can easily reproduce the same environment without an internet connection, provided you have virtualization enabled.
If you ever need to change something, download it on the virtual machine, run whatever sanity checks you need to run to ensure everything is up to standards, and repeat the same process of creating new ISO, destroy the previous virtual machine and deploy a new one.