Not 100% an answer to your question, but I was able to start reading reading Japanese fantasy novels around mid-B2 while using a dictionary and likely could've started earlier at the cost of more pain (and it was already plenty painful). Neither other languages I speak are even remotely close to Japanese, so you can put lower B2 as an upper bound. With that in mind I could see upper B1 if the languages are close like in your example and the subject matter is on the simpler side, but A2 ain't happening. At that point you'll struggle too much to understand the grammatical expressions in the text to comprehend the subject matter.