My kid won’t poop

My oldest will be 4 years old in a month. She has always been VERY headstrong and I learned early on that she does things in her own time and not a moment sooner. As she’s gotten older, there have been a couple instances where I tried to just let her figure things out on her own, but it got to a point where we had to borderline force her.

Primary example is potty training. We stripped her naked and chased her around with a potty chair for 3 days after she turned 2 and it just didn’t work. She wasn’t getting it. We tried again a few months later and she was very defiant about it, but I could tell she had a better grasp on the concept. We had to finally hold her on the toilet (screaming and flailing the whole time) until she peed - and then once she’d done it, she was fine.

In hindsight I realize this was a mistake, but we didn’t tackle poop at the same time. We were just so emotionally drained from the training we had already done with her. So she would poop in a diaper but had to be in the bathroom when doing so. We tried transitioning to having her sit on the toilet with the diaper on but she was not having it. She was insistent that she had to be standing up.

When she turned 3 we tried again and told her that when the diapers were gone we wouldn’t buy more. We warned her every time she used one “there are only X diapers left, then we are going to go on the potty.” We read the books, did all the prep, and when the diapers finally ran out she ended up withholding for a week, stopped eating, wouldn’t play, and I ended up giving her a suppository. It was very traumatic, she literally screamed one night from 8pm-3am and wouldn’t stay in her bed because she was so stressed about the whole situation.

We gave the diapers back, and I talked to her pediatrician who recommended trying mirilax once we let things calm down. Now that it’s been a few months, I started giving her the mirilax and lots of foods to help move things along. Then we went cold turkey and told her no more diapers. She is on day 3 of completely withholding, she’s absolutely miserable, hardly eating, belly is bloated, and I have to beg her to even drink water bc she has made the connection that it’s harder to withhold #2 when she’s peeing. She’s having trouble sleeping and is generally not acting like herself.

I know this NEEDS to happen. The diapers are just a crutch and we need to win this battle of wits/power struggle. I’m just concerned that something is going to happen medically with her withholding and not eating like this.

Have you been through anything similar? How did you navigate? We have tried bribery (sweets, toys, experiences), she is not allowed to watch tv until she goes in the potty, we’ve done the sticker chart, we’ve read ALL the potty books, we’ve made up potty songs and games and dances….its still just this insane power struggle.