I agree that the pull ups have to go, easier said than done I know.
My daughters are also autistic & very bright.
The whole situation & topic for her is all anxiety, fear & pressure at this point & the more time that passes the worse you feel & she feels.
Kids are smart & I know you’ve taken a relaxed approach but I would bet that she knows just how badly you want her to do this & of course it’s out of love & I’m sure she knows that too:)
I haven’t been in this exact situation but I’ve been in many with my girls that felt like the task or issue would never resolve.
I would lighten this up with humor, if it were me, & it sounds silly but I would get a water gun & while she’s sitting on the toilet spray her backside & make a joke of it.
Use her intelligence to your advantage & say “this is what might happen if you go, you might get splashed like this”
& laugh. You have to try to drain this anxiety from her & you don’t want it to start affecting her self esteem. I tell my girls, at least weekly, that we all have struggles & I would tell her that right now this is her struggle but you’ll get through it together.
I really hope this advice helps you. I could feel the frustration through your words & I’ve been there so many times. 🌸

LOVE, LOVE, LOVE your idea about the squirt gun!! Wish I had thought of that all those years ago!! 🤣🤣

We get so damn exhausted and we wrack our brains trying to think of things to use to get things done. It's so difficult!!

I did forget one thing in my post...don't know if it will help or not, but I discovered that my son loved those "star" stickers...so, I put a calendar on the back of the bathroom door and everytime he went in the pot...poop or pee, he got a sticker. He LOVED filling those spots up...don't ask me why! 🤣🤣

I tried toys, CANDY, special treats like donuts....he refused them all! But, stickers, he was all over it! 🤣🤣

Maybe her favorite type of stickers would help as well.

Great idea about the squirt gun! 😊😊👍👍

What makes her laugh?
What distracts her?
Allow her to take a toy or her tablet in there as she's on the toilet.
Laughter helps the stomach muscles move the fecal matter.

You have your hands full with this issue, for sure. Your daughter sounds a lot like my son. Very bright.

He wasn't fully potty trained until he was 7 1/2. And, the pooping was the last thing as well. I used suppositories ALL THE TIME because he withheld ALL THE TIME! It went on for a long time, but I just kept at it. Kept putting him on the pot for 15 minutes at a time every hour. He loves to read, so I used books....potty training children's books.

When he got constipated, and I used the suppository, he had no choice but to poop in the pot, and by that time, he was in so much pain, he welcomed the relief. Where I think your first move would be is the pull-ups.

In my opinion, you need to wean her off those before anything else will move forward. Your gonna have to start slow, of course. Maybe one time on the pot for the week without the pull up when she has to poop and the rest of the week with. Even if she doesn't poop and you need to use the suppository. She has to get used to the fact that they are going to be gone before anything is going to happen. She's got her safety net with those pull-ups. If you don't start removing it, she's gonna just keep doing what she's doing. Of course, she's going to resist. All the way. There will be tears and anxiety. But, eventually, one day, she will poop in that pot.

My son is 33 going on 34. He does his own self-care in this area and has from 7 1/2.

I know it's very tough. I thought he never would do it. I was exhausted and very upset about it. Bit, I just kept at it.

My advise. Start the weaning process from the pull-ups. She will get there. If you don't, she has no reason to change her bathroom "secret."

She WILL have anxiety with this, but as she gets older the anxiety will increase with her continually trying to hide it from others....because, as you say, she's aware. Very aware.

Good luck. My best to you. 😊😊😊