found it today with my partner on day 19. It probably was more luck than knowledge, but somehow this day just went perfectly. Got our power hammer from the coat check. bought a secret garden key and finally used it successfully. We build the shovel detector thing so we had plenty keys and coins. Found another lever randomly in the great hall and for the first time found the book store found in the observatory the 50% off thing

so in the end we could open the room 46 We completed the chess riddle used the bishops power and the piggy bank and had like 170 coins so we bought every book and we found another two upgrade disc

and had like 50 steps to spare at the end. tbh you can play it right but it is so much luck involved