I free myself of all negativity as it doesn’t belong to me nor define who I am.

Some of the harshest things you say about yourself, you did not write. You picked them up — a phrase an adult used at a dinner table when you were small, repeated often enough that it stopped sounding like anyone's voice and started sounding like a fact.

You can usually find the original speaker if you listen for the accent.

That is the whole trick. Once a thought has an author who is not you, it becomes a quotation rather than a verdict, and quotations can be set down. It will not vanish. It loses its authority, which is enough.