Unlike hunger and thirst, Sofia still gets exhausted/tired somewhat like a regular human. She still dreams like a regular person and is usually very groggy and slow when she first wakes up, unless woken up by a load sound. Sofia is also a very heavy sleeper, with the Orb being the only one to wake her up quickly by controlling her. However, while she gets tired normally, she does not need to sleep as much as a normal person does and has spent weeks awake with little issues due to Helel affecting her mind so she doesn’t feel the effects of sleep depravation.
Also, if Sofia transforms in a dream she will also transform in real life. So if you see her cuddling her spear, she probably fell asleep while watching some on her phone, and then found herself in a dream where she had or felt the need to transform.
Nullie on the other hand, has never slept and will never need to. She can sleep, however as she made her human body to match those of humans as closely as possible.