Mod folders, GOG, Mac?

Hello, I'm unable to find the folders I need to extract mods to on the Mac version of the game bought from GOG. I don't have anything for Project Hospital in the Application Support folder and there is an empty folder within the .app contents titled "plugins", is that the right spot?
Thank you

Good afternoon, I'm some months late, but the mod folder should be somewhere:

"~/Library/Application Support"

/Project Hospital/ProjectHospital_Data/StreamingAssets/Addons

I know you wrote you checked Application Support, but try to click on Finder, then to Go To and paste: ~/Library/Application Support

There might be some Application Support that is not accesible other way.

Regards,
Crinlorite.