The two way street, and why it lets you off one hook

One finding in the research above is worth pulling out and holding.

The relationship runs in both directions. Harsh discipline predicts more difficult behaviour, and more difficult behaviour draws more harsh discipline. A child who is harder work pulls harder parenting out of the adults around them, and that is not something you decided.

So the honest picture is not that you have been doing this to a child. It is that the two of you are in a loop together, and one of you is an adult with a slightly better view of it. That is not blame and it is not exoneration. It is the reason a small change by the adult can move a thing that felt fixed.