If you can get access to your Steam version of the game, you can find the DLC files in the "game" folder (you can access the game's full folder by right clicking on it in Steam and going to "Manage" > "Browse Local Files"). The DLCs are files with .rpa at the end. You can send those to yourself via email, or Discord, or something like that. Then, simply put those files into the "game" folder on the Mac version, and that should work! If you need more help, just let me know.