I am running civ 6 build 1.0.0.26 (143190)
on my Mac. Purchased it using Steam.
How can I either confirm that I am running the latest build or force update?
Make sure that Steam is not in offline mode. Then try to launch the game.
If the game is not up-to-date, it will update before launching the game. If the game is up-to-date it will just run.