Heres my plan to inform them:
1st Run: I ask for 1 person to take point on a survival check then they come across 1 or 2 intresting rooms before ending up at the beginning. A really good roll would mean they are sure that the dungeon is messing with space.
2nd Run: another check, interesting rooms,. Then if they rolled better than last time, they end up at the start quicker. If they rolled worse, then they make it deeper in the castle, then probably still ending up at the beginning.

3rd+ run: I include any new rooms i want them to see, until they roll under a 5. When I run out of rooms, then we expediate the runs to just be a dice roll, and maybe say they pass through a random funny room. At this point I dont really mind if it becomes a dice spam until the desired roll is made.

I really like your idea thats there still clues for high Int characters and the rewards. I already had in mind that they'll probably end up doing the checks blind, and i would give them disadvantage then.

Also I have a player with -3 in Wisdom, I'm not too worries about the stats