No one can, or should, deny their biological sex. A trans woman is not the same as a biological woman, however you want to live or identify yourself; a trans man is not biologically male. The distinction is important. Identifying as the opposite gender to that encoded in your DNA is to betray your own body. And your body makes up a large part of who you are. It mediates the experiences that form your character, even more than your verbal declarations, through its hormonal, emotional and sentient biome. Other people recognise and react to you as a physical, emotional entity more than as a package of ideologies (at least in your real, off-line relationships.) So, to reject your own body seems likely to lead to an even greater crisis of identity.
Adherents believe you can be biologically male but “truly” female, ignoring all the operations of your biology on your psychology and experience of life and community, despite never having been treated as a woman or experiencing menstrual cycles or giving birth or lactating or being sexually threatened. This is self-fulfilment seen through the lens of consumerism. If you can shop like a woman, you can shop for womanhood. You can buy your own vagina.
The belief that such existential angst is caused by being the “wrong” gender and would be solved by transitioning, seems naïve, to me. I don’t imagine being female is any more fun than being male and it does not solve the puzzles of how and why we should live. I guess it could create obstacles that you can pre-occupy yourself with overcoming, which should pass the time, allowing you to avoid confronting the hopeless, pointlessness of existence. (Like anorexia.)