Hi need some help

I have a feral cat named bell i got a month ago but she has been in the hospital since last month .i got her back today and I really want this to work but i am not sure it will .i have 3 dogs 2 pugs and 1 golden retriever there quite used to her presence but she isn’t .and i am not sure if she used to mine.

She lets me pet her and rub her head but she doesn’t seem to enjoy it and i leave her in my room. Unlocked most of the day but she stays in ur playpen in this cardboard box I made her as a den .and when see does leave she often hides what do i do ?