If your kid pee trained easily but only pooped standing up in a diaper/pull-up, how did they get past it?

My son is almost 4. He will sit briefly, but when the poop urge comes he jumps up and asks for a diaper. Then he stands and likes to holds onto something, like the bathroom counter. The most common advice for this seems to be to make them wear the diaper while sitting, then gradually take it away by cutting a hole in it, OR completely take away diapers and wait them out. If your kid had this problem, I’d like to hear how they got past it and how long it took :)