Why is there a waiting time for playing a chapter?

Congratulations, you have caught up to the developers! By design, the developers only release one new chapter per week. They have done this since the game began, allowing them a regular schedule to produce new scenes, with exception of holidays and time between volumes.

Most recently, on Dec. 16, 2021, they released Volume 5, Chapter 25 (scenes #1171-1175). Even though players can increase their levels beyond this, they cannot play the scenes until the developers produce and release them. One chapter (5 hidden object scenes and 1 adventure scene) is released every Thursday.