I get that, and it make sense that a goddess putting a contract out on the heroes would know all sorts of intimate information about them and give to Shiryuki. it just makes it less exciting when she has less to figure out.
I mainly blame the pacing, if they didn’t have to force entire arcs into two or three chapters, I would like to see some more detective work on Shiryuki’s part. The kill would have been a lot more exciting if freeing Lunatic and using the barrier against the heroes was improvised after exploring the towers instead of just following an omniscient goddess guide book.