That's what I ended up using, in order to avoid repackaging the installer I built a payloadless deployment (dummy/empty .pkg, unsigned as it doesn't matter if it fails to run, followed by a post-install script that downloads the latest installer for each software to deploy, install them, then delete the temporary folder.
At least they give the ability to be really specific about what you want to deploy using the Configuration XML file.
I wish they offered something similar on macOS.