We had a similar problem with our 3yo at the time. She would make herself constipated and hold it in for days, which made the experience even more painful and exhausting.

I see you said you tried forcing, but that’s exactly how we got through it. I literally held her down on the toilet until she just let go of it. I wouldn’t let her get off the toilet, and it only took about 10 minutes. She did it, realised how easy it was and that it doesn’t hurt. We rewarded her the first couple of times, especially when she would go by herself. Then it was never an issue. He will figure it out, hang in there Mumma, you’ve got this.

I think its always associated with being negative by the sounds of your comments. Maybe change it up and be positive and provide encouragement during the times he messes up. A reward chart may also motivate him

put him on the toilet at regular times like after meals and just keep positively encourage using the toilet. there is also some good books about going poo in the toilet.

Oh wow, a tough one! As he was tough to toilet train to begin with, it might just be a case of more time for the number twos on loos to happen. Try and avoid the growling and chasing down though, these will only be making his fear worse

He might be scared or unsure apparently boys can get quite funny about the poo side of potty training. If bribery doesn’t work try and see a Doctor to see if you can get to the bottom of the cause. You definitely aren’t alone so don’t lose hope.