Transmedicalism is a harmful ideology often perpetuated by transgender people trying to appeal to transphobes in an effort to seek validation. It is intertwined with the concept of medical gatkeeping.
To put it painfully basically, transmedicalism is simply the belief that you must have gender dysphoria to be transgender. It sounds reasonable on the surface as the vast majority of transgender people do experience gender dysphoria, until you pry past the basics label and look into the ways that transmedicalists (those who believe in transmedicalism) behave and treat others.
Some transgender people find it easier to explore their gender through gender euphoria, and rarely (if ever) truly experience gender dysphoria. Even those who do experience gender dysphoria all have their own unique experiences with it. There are countless ways in which one can be dysphoric. Different people have different levels of gender dysphoria, ranging from mild discomfort to extreme self-loathing.
Transmedicalists believe that you must have every possible variation in the maximum level of distress regarding your gender identity and presentation without exception. They believe that to be transgender, you must get (or want to get, if you can't afford the costs) every possible gender affirming surgery or treatment. This of course, excludes nonbinary people, as well as many binary trans people who are still comfortable with certain aspects of the body they were born into.
Transmedicalism is often used to gatekeep who is or is not considered transgender. It is used to bar those with nonstandard presentation from accessing gender affirming treatment. It is used by certain transgender people to try and appeal to transphobic cisgender people, to try and seem "normal" and appeal to those who are not generally accepting of gender variance. It is a failed attempt of gaining acceptance at the cost of putting down some of the most vunerable members of the transgender community.
Transmeds will often bully those who are nonbinary, gender non-conforming, or simply disagree with their hateful rhetoric. They cause more harm than good, and deserve to be ignored. No one is helped by being forced into the closet simply because they do not wish to be the pinnacle of masculinity or femininity.
The term "tucute" is used by transmedicalists to refer to nonbinary and transgender people who experience little to no gender dysphoria as an insult.