Figma make doesn't see my already published library

I’m struggling with the exact same scenario.

I think I get it now. It looks like Figma Make is only capable of accessing libraries published at the team level, not the organization level. If you publish at the team level, you will be able to access it. Publishing to team won’t affect your source of truth. 

Something to be advised of if your using token studio in your library, you will have to export your tokens into Figma as variables. Make is not able to tap into the 3rd party plugin.