If trans people are suicidal and unhappy with their assigned gender, and they require treatment(hormones and surgery) to feel better, then isn’t it pretty clear that they are indeed mentally ill?

Trans people have brains that are more similar to the gender that they identify as than the gender that corresponds with their biological sex, so this results in gender dysphoria, where they strongly desire to become the opposite gender, and are discontent with the sex they were assigned at birth.

To speak bluntly, their brains are abnormal. Many are suicidal as a result of this “abnormality”, so they are given hormones and sometimes surgery to make their body match up better with their brain. Now, because they require treatment in order to become mentally stable(or at least more mentally stable), doesn’t this mean that they were mentally ill? If you weren’t mentally ill, then why would you require treatment?