I think this is a resulting behaviour NOT a deficit. teaching a child to seem to play imaginatively is not going to make them less autistic any more than masking the hormones in your pee so you don't trigger a pregnancy test will make you less pregnant
If I understand correctly; learning the child with ASD, to play imaginatively, is more to do with social imagination? Rigidity?
Ds didn't really have issues with rigidity, though he was delayed. But when I helped him with his imagination skills; he became less rigid as a whole....I can't quite explain it.
It's so weird how you can tell where the child is developmentally at by the way they play. When DS was rigid in his play...eg.. not allowing people to play with him, this also reflected outside...
Anywhoo; OP I agree with you. I don't think stimming is bad, but I find that when I leave DS to his stimming, especially when playing, it was like he was locked in... or for example; say like DS just kept on banging blocks repetitively in his play, I felt like if I didn't intervene and helped him to expand his play, he wouldn't progress as such. When I did lots of turn taking games at home with DS; this worked a treat when I took him out. So before when I took DS out somewhere, he didn't like to go to a particular (boring) place of my choosing, he wanted to go to where he wanted to go. So as I did lots of turn taking games with him...and when I did take him out, I would tell to DS "It's my turn (to go to the shop), then it will be your turn to go (wherever he wanted to go". This enormously helped him.
The power of play is indeed powerful.
OP; I really recommend you to get the book from the teachmetotalk website called "TEACH ME TO PLAY WITH YOU" manual. It lists and gives instructions on how to play with your child..what to say etc and on the back of the manual (book) it gives you a list of the common concerns regarding play...eg if a child has difficulty turn taking, it will give you ideas on how to help your child deal with turn taking and so on.
Can you find what your child like, that can transfer into useful play? When DS was younger, he would stack things, and he liked to build things. So I brought him jenga; taught him how to play with the blocks and he will do it himself..I also got him lego and he liked to look at the instructions whilst building it. This in a way expanded his play skills and allowed him to enjoy an activity.
OP! you say your daughter likes playing with sheets of paper. I really recommend you go to your local library and find a book about sensory games activity, maybe this is sensory...so the book will suggests some sensory games you can try with her.