All three are absolutely fantastic.

For me I think I would put Shadow of the Erdtree at the top, because of the sheer volume of content and ambience it added to the game. I absolutely loved all the main remembrance bosses and the new locations added. Rauh was so different from previous locations From did and so good that I now want a jungle themed game from them so bad. I also love the last boss fight, it was challenging as hell.

Ringed City and Old Hunters are tied for me. Like I absolutely love Ringed City, the last boss fight with Gael and how it finished the series, but Old Hunters made me fall in love with Bloodborne, even tho I was so over leveled for it I demolished the DLC. I absolutely love the Fishing Hamlet, it made me feel like I was inside a Lovecraft book.