The good news is that you don't need it, and can easily have dozens of hours of enjoyment with just the base game and free DLC.
Combined, there are no less than six full paid DLC factions (Brettonia is free in both games) and six paid Lord/Unit packs between both Total Warhammers. To be frank it can be somewhat intimidating to scroll slightly downward and look at the sheer amount of additional content you can purchase when you also factor in the first game. While Total War: Warhammer II routinely drops to around $20 during various Steam Sales, that'll only get you access to around five of the factions I've ranked here. Let's talk about DLC content and pricing If you wanted to know why my RSI is acting up, it's because Amid Evil is the most fun, visually striking twitch shooter I've played since DUSK.
It's been a nice writing exercise, and a good reminder that I can try and follow a prompt of my own making, but now my RSI is acting up and it's time to wrap things up.
We've managed to reach the end of my Total War: Warhammer ranking list, an endeavor that accidentally became way more of an endeavor than I thought it would be. Here's Part 1 and Part 2, for your pleasure. Ranking of Factions: Total War Warhammer II (part 3)