Currently mod zips show up in "C:/Users/user/Paradox Interactive/Europa Universalis IV/mod" after subscribing. This works slightly different now. Mod zips (Now named *.bin) will now stay in the Steam downloads folder (Something like "D:\SteamLibrary\steamapps\workshop\content\236850\217416366",
I'm guessing there's a technical reason for this, but I'm sad to see it tbh. I know that you rarely have to go in there (if you don't mod yourself, probably around never and even then it should be rare) but when you need to do it, the structure in the workshop/content folder is really annoying since you a) need to find the correct game ID you usually don't know by heart and b) if you have that, often the mod isn't that easy to find because you find another folder full of folders with simple IDs. If you are lucky the .zip is sensibly named and you can use the search function. if.