Unicorns don't spawn in wizardry dimension, wizardry github says this is an issue with the version used and is fixed in later versions. updating the mod manually would be a pain as around 8 of us play on a server so we would all have to do it ourselves. Any chance of the mod being updated in the modpack?

What version of the modpack are you using?

5.12.1

Update. 5.12.3 is out and has the updated mods