Hi there! So I looked this up myself and got the same results about the Edo period stories.
Thing is, I looked at another title card for the main missions that read 仁之道, which I translated as “Jin’s Journey”
In the journal menu, that is the heading for all of the main missions, so I’m guessing the other two also correlate. I haven’t seen the card that says “Tales or Tsushima” lately, but I seem to recall it as saying pretty much that, so I’m guessing it’s supposed to be the third option “Mythic Tales”. I would say that the card should have read something like 神話物語 but maybe there’s something I’m missing like how the existing card might have some nuance I’m not getting, but maybe it’s just bad translation/QA.
Edit: Having played a bit more, I was wrong!
仁之道 = Jin’s Journey
傳承 (Old kanji, now written 伝承, lit. “folklore”, “legend”) = Mythic Tales
So yeah, those kanji are probably supposed to mean “Tales Of Tsushima”. Again, I might be missing some context, it might be a bad translation, or maybe these are the sort of tales that were popular in those Edo period writings? Maybe that’s the connotation?