Next to the bed. You have ton unlock more gallery. It's probably why you don't trigger the next dream.
i have 3 locked animations on my book there is hint for one animation 'start solving academy greatest mystery' as for one next to bed i noticed siluets of protagonist and trainig dummy is that related somehow ? im really lost now, i beated each location at least twice ;-;
BTW there is a bug when each time i launch the game and spawn in bedroom dialogue appears 'you will need to slay lay and spellbind the essence of a very powerfull hellhound to unlock the next seal have fun'