Hello, I know this might be a slightly older post....but it holds a lot of merit. I would like to know that as well. I have considered getting the Deluxe/Gold editions of UBISOFTS games, but I have seen from reviews that DLC will either not activate/work or has disappeared from the listing over time. Thank You

Well i have not found a handy list but on https://www.pcgamingwiki.com you can see if DLC is accessible and they even provide patches where you can still enable DLC.
Why Ubisoft removed the list on their own website is beyond me https://web.archive.org/web/20220929223838/https://www.ubisoft.com/en-gb/help/gameplay/article/decommissioning-of-online-services-september-2022/000102396