There's a button on the git page to download if you look more carefully. If you still can't find it, look up a guide.

Recommend Rimpy for this, it's got tight integration with SteamCMD which is a command line tool from valve that can pull from the workshop without an account that has the game. Git is one option but keeping it updated is gonna be a chore. I know there are some sites out there that archive workshop content but you have absolutely no guarantee the dll's they come with are clean, the downloads are slow, and a lot of times they're not the latest version.