These are not my favorite terms, but, there are ways for Masculinity and Femininity to both be toxic.

Assume we're talking about normal men and women that want to be men and women. Gays and Trans people are outliers.

Feminists tend to focus on how masculinity is toxic to men, and mostly ignore or deny femininity being toxic at all.

But this misses much of the picture.

Masculinity can be most toxic to women, and Femininity can be most toxic to men. Toxic in the sense that, they can hurt the person's well being and overall state, imbalance them, hinder their self actualization.

A boy that's treated like a girl growing up, allowed to be feminine, while not being pushed to have his masculinity developed, ends up not being able to well figure himself out, what he likes, or is capable of. Non-competitive, fearful, sensitive, or soft men are manifestations of this.

A girl that's treated like a boy growing up, pushed to be masculine and is allowed to have their femininity neglected, she too ends up confused about who she is and what she likes. Tough, overly independent, distrusting, closed to emotions, highly competitive, or domineering women are manifestations of this.

Both of the above can generally be addressed by men also developing their masculinity, women also developing their femininity.

However there is also toxic masculinity in a man in the sense that it can make him overly violent and risk taking, emotionally closed.

Whereas toxic femininity in a woman can make a woman use her sexuality and seduction too much, and be too emotionally controlled.

The reason toxic masculinity and femininity manifest and affect men and women differently is because masculinity and femininity play off each gender's nature differently, play off of their drives and tendencies differently.

Feminism too tends to promote toxic femininity in men especially with its demonization of much of masculinity.