I have only the base game but I don't see this being a perk location for a DLC or the Prophecy. You can see there I am above 40 so I should be able to play this, what might be the issue? Also, I have the same issue with some other locations like just in this sector the Mining station 121 and the Tempestus Citadel.
PS.: In the General Tutorial, it says the Cathedral is in the Chernobog System.