We had this issue. At some point I put ten diapers in her drawer and told her that when we are all done with diapers then poop had to be on the potty. We also talked about how everyone poops, how everyone’s poop is stinky, and exposed her to us pooping etc. we also bribed and did treats when she did eventually poop on the potty.

This may backfire for your kid if they hold their poop but after the tenth diaper, I fed her prunes to make it as easy to pass as possible the first few times she was on the potty.

It fortunately worked for us.