Help with stubborn 2.5yr old

Ok everyone I need ideas or something. My 2.5yr old is one stubborn, strong willed, independent, doesn’t like to be told what to do toddler.

Issue is, she is pee potty trained but will not for the life of her will not go poop like at all. She will hold it and hold it. It’s gotten to the point of me having to do manual stimulation and a lot comes out. When she does go poop it’s like a huge Lincoln log. Have been giving her mommys bliss constipation ease for softening and miralax. She won’t he prunes or drink prune juice. I am one NOT to give juice anyway. It’s not constipation as 99% of it all is soft, it is just her mind and attitude of her not wanting to poop at all. She will throw a complete fit over it. I can’t get her to sit on the toilet but daycare can and she will sit there for at least 30min. Lately it’s been her sticking her fingers in her rectum and getting poop everywhere having to have a bath afterwards.

I don’t know how to fix this issue.

Add: she does get rewards for going potty, have tried to give her books, toys etc while sitting in toilet.

Add again: this is an issue of attitude and mind set. It’s absolutely pure refusal to do this task.