I literally just played it again to test if it's broken and it's fine, as long as your version is the same as itchio's latest one.
Here's a step by step on how to unlock the sleep:
1. Go to Deck Manager > Buy 4x of the first Bronze packs > leave Deck Manager
2. Go to bedroom > Open Wardrobe > Close Wardrobe
3. Go to Juliet Room > Open Bag & Equip the only item in there > Close Bag
4. Return to bedroom, you can sleep now