So is blatant!
It’s mathematics, it’s not hard to tell if a bunch of bits is random or contains a pattern. True randomness is very hard to do. Once data is encrypted it still can contain some non-randomness that can be discerned. The job is to decrypt to the most non-random state you can. The most non-random state might still be something like a simple book cypher so it won’t be readable yet...or it could be plain-text.
Subtle steganography is a real headache for those looking for secret meaning in masses of data.
So is blatant!