I would disagree.
It may be true for those who feel that they were born in the wrong body and are dealing with dysphoria issues. However, that is not the only definition for being transgender.
In my case, I have never felt that I was in the wrong body. If I have any dysphoria, it is minimal. However, what eventually occurred to me was that I am an amalgam of masculine and feminine genders, perspectives and likes/dislikes. While my chosen presentation is feminine and I present as DeeAnn 95%+ of the time, I am not anticipating HRT or any surgeries. In all of my volunteer, charitable and political work, I am known as DeeAnn. In the 7 1/2 years since I retired and relocated, perhaps fewer than 20 people know that Don exists. How things work out for me is that I have a number of masculine interests and activities that stand alongside a number of feminine interests and activities. It is just how it is.