My goal is to be able to do all steps of the typical Meshtastic youtube tutorial without access to the internet.

I like to liken it to my other hobby of retrocomputing. In the old days, your whole OS and all the applications ran from a few floppies and a couple of books for documentation. If you need to duplicate the environment, just make copies of your disks. And of course you need an original set to start with. But nobody thinks of that as "offline", that's just the normal way it works, and yet it seems more offline than modern projects who claim to be offline.