Parents are people before they are parents, though children discover that late.

There is a moment, usually late, when a parent becomes a person. They had fears, disappointments, a life underway before you arrived, and were making decisions with incomplete information while you assumed authority meant certainty. Seeing that is uncomfortable because it removes a figure and returns a human being. It also makes a lot of the past more understandable.

Ask a parent, or someone who knew them, about a period of their life that has nothing to do with you. What they were worried about at your age. The answers usually change something in how the old grievances sit.