Unless you want to commit to the position that people with mental illness should just deal with "the body they are genetically and biologically predisposed to" (have we abandoned that as a metric that is useful yet? You appear to have jumped to an entirely different set of criteria for what is important), you should probably reassess your argument.
Here are some other things that are "mental issue[s] that make[] people feel bad":
Anxiety
Depression
Bipolar Disorder
Schizophrenia
Paranoid Schizophrenia
Obsessive Compulsive Disorder
Post-traumatic Stress Disorder
On the other hand, I don't know anyone with gender dysphoria so I've got no horse in this race.
There's just been an episode of Rubin Report with Blaire White which talks about this but haven't got around to it yet.