Logan had cultivated to the Quasi-Saint Realm, and such talent was indeed rare in a century, perhaps even unprecedented. However, his claims about his alchemy and array prowess were clearly exaggerations, not to be taken seriously.
Back in the Ancient Secret Realm, Logan claimed he had trapped two members of the Holy See with his array skills. At that time, they didn't refute him, but deep down, they greatly despised him. They were all in the Saint Seat Realm themselves; how could it be possible for an Array Master to corner them to death? What did they think of Sanctuary Powerhouses?
If it weren't for the fact that Logan had the ability to pass through challenges, and everyone needed to rely on Logan during the time in the Ancient Secret Realm, they would have exposed him long ago. Now, naturally, they didn't have so many concerns and would not indulge Logan.