Ours was similar. Our home introduction was one bedroom for a week. (Food, litter etc in there...naturally he bonded with me first as a result. It became his safe place. Even now, it is his place to go to chill out and nap. Some cats are wired like that. Others may be from trauma. Mine was shipped from BC to Toronto in a crate with a thin little towel and nothing more. He is our skittish one. Why, who knows. Too much too soon will frighten some. Backtrack and try one room for a week, then one level (but revert to that one room when you are not home), and expand from there. For 2.5 weeks, if no one home, he was in my room. Also, remove ability to hide from that room. We boarded up under the bed for example. If they can hide, they will. A safe room that forces them to explore is what they need. My room had food, water, litter, tubes to play in, scratching post, a way up onto my bed, and a TV for light noise when alone. Try that.
Cat treats in a carrier may entice her.
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