This Steam goofiness has no effect on mods you manually download and unzip from here or elsewhere like reddit. Macs are located somewhere in something called 'Libraries' as I recall from what people have told me.)
(btw the specified folder-path is for Windows machines. They are sent to folders with numerical folder-names that match to the Steam Item's ID #. All your downloaded mods will be folders within this '289070' folder. '289070' is Steam's designation for Civ6. Steam in all its wisdom has decided that mods should not be downloaded from steam into the game's pre-provided MODS folder but rather in a 'Content' folder at C:\Program Files (x86)\Steam\SteamApps\workshop\content\289070
