Possible fix for free DLC issue I haven't seen yet.

Making this thread because I've had an issue with some of the FLC that no one really described and to help people that were tearing their hair out like I was.

So I never really got on the Warhammer bandwagon until Warhammer 3, so I never downloaded any of the FLC before. I bought Warhammer 2 just to play Immortal Empires and I had Warhammer 1 in my library but barely played it back in the day.

I couldn't get much of the FLC to unlock, when I would click the add to library button it would just say "Couldn't add to your account, try again later."

I figured out that for this FLC, you have to click "Download", but don't initiate the download, this will attempt to install the game with the DLC - I.E. if the FLC is for Warhammer 2 steam will attempt to install the whole game. Just cancel the download and then go back to the store page and it will be unlocked.

After doing this for each of the FLC, close steam completely and open it back up. Then check in game, they should all be unlocked.

I hope this works for other people that have the very specific circumstances I have.