How to open prison cell doors with the Purple Seal in Pagoda Realm in Chapter 3 – Black Myth: Wukong Guide

Since there's nothing else to do here at the moment, continue along the ledge (past the lantern guards when the room is in its grey haze) to the realm's first Guardian Shrine. Just before the shrine, you'll see another of the locked purple doors.

From the Guardian's Shrine, go left and into the prison cell so you can go down the tunnel behind it. Follow this until you reach the end, where you'll end up outside again and on another part of the ledge. Follow it (past the lantern guards again if it's hazy) to the opening on the left, which will take you to a staircase.

Go up the stairs. When you leave the cell you will see that the path branches off to the left and right. Take the path to the right and go back until you reach the wooden beam. Use this as a bridge to reach the smaller ledge (watch out for the archer along the way).

Go through the passage on the right until you come to an enemy standing on the wall near a drop that will take you to the next level. Then go past the red-haired Yaksha to get to the next Guardian's Shrine.

Opposite the Upper Pagoda Guardian Shrine and past where you just walked, you will see many stone figures. Carefully drop down onto the roof and then look for the lower roofs on the left to safely descend.

As soon as you approach the large figure, the boss fight against Captain Lotus-Vision begins.