Ohh man I could never get into EUIV fantasy mods. Always felt that they'd suit CK better. The only exception is probably the Third Odyssey mod. Then again I always liked CK more the EU.
Anbennar is a special case, I think. It really leans hard into the existing EU4 mechanics in places, and then does fun things. Immortal elven rulers suffering decadence, war wizards leading armies, dwarves that delve too deep unleashing Stellaris-like invasions from off-map. But then it adds a bunch of amazing things like magic systems. Maybe your ruler wants to study necromancy and become a lich, raising armies of undead to ... farm the fields so that your economy doesn't have any peasants. Etc.
One of my favourite things is the racial militaries. Harpies can fly, so they have insane siege bonuses. Centaurs are a pure cavalry military cause, well...
Worth it if you've never tried it. There's probably more content in this mod than the base game by a factor of two. Start with Lorent (France equivalent) to learn the mod mechanics, then try something more interesting like Frozenmaw (Orcs) as your second run.
What I would like to know is how to track the development and releases for this mod. It seems pretty difficult to get this info, if you do not want to give up your privacy and join their Discord.
I read in some discussions that right now, the release that is available via Steam Workshop is outdated and buggy on latest game versions, and that they are working on an update. But I can't find anything useful anywhere about it.
If you're playing on the Steam Workshop version, at the time of this writing, you will need to rollback your Eu4 to previous release to make it a smooth experience. If you're using the current Eu4, you can check out the development branch through git. If you're worried about privacy to the extent you seem to be, you probably aren't on steam anyway. Nevertheless, here is the link to the git repo of most recent version:
Steam doesn't want my phone number just to sign up, Discord does. :)
This is all general info, which I more or less pieced together from various forum posts and the mod description on the Steam Workshop - but thanks for confirming it.
What I was looking for is some table summarizing which Anbennar version works best with which game version. And ideally versioned tags in the git repo - or release tarballs, whichever is easiest to maintain for the devs.