There's so many layers to Ephie's loneliness
I wonder if it has something to do with her not having a cat. It seems witches tend to get the unconditional love of their cats regardless of anything, they are literally born for them.
But Ephie was able to get the unconditional love of her adoptive dad for a while, then got attached to the mechanical cat right after, she only put up with Bibi after cause she didn't have anybody after
Seems like a really sad existence, it makes me wonder if Witches are capable of unconditional (not getting anything in return) love themselves