I have fixed the Beast Book issue (a LOT faster then I expected) and now you should be able to complete the Beast Book wayy quicker, since there is only 1 entry per enemy! This probably will require a new save though!
Thanks, but honestly, having to start a new playthrough (because of the bestiary issue) in order to access new (end-game) content was the straw that broke the camel's back. I just wanted to let you know that I've moved on to other games for now, and maybe I'll give "Rift Walker" another try once it's in a complete state, but not anytime soon.