So, WandaVision's Darkhold is a way different design than the Agents/Runaways version. Despite this, those involved have said that they believe it to be the same book. I just can't reconcile that in my head. To me, it's clear that the two books cannot be the same object (or rather, a very convoluted explanation would be required for the difference in design if they are the same book). Thus, my view is that there are two Darkholds in the MCU.
WandaVision's Darkhold is the original, much older tome, and may have once filled the empty slot in the Kamar-Taj library.
The Marvel Television Darkhold is a much more recent copy. As it has English on the cover, it can't be older than about 500 years. My headcanon is that some sorcerer used the original Darkhold to create the second Darkhold. This copy is still a very powerful object, and can be used to access all the information contained within the original. My theory is that this second Darkhold acts kind of as a search engine for the knowledge in the original (which is why the pages are blank until someone reads it).
What do you guys think? Anyone got a similar theory? Or a completely different one?