Any promotion of the concept of gender and gender roles in schools is a bad idea in my opinion.
Gender is a concept that exists. That kids will interact with throughout their lives. They deserve to be equipped with the information that helps them makes sense of that.
The “genderbread person” that pops up is one instance, and it’s discussion of gender includes gender roles: those are societal expectations of actions and characteristics.
It doesn't include gender roles in any version that I have seen.
The closest I've seen it get to gender roles is "gender expression", which it touches on to explicitly separate the concept of gendered expression, from gender identity and biological sex.
In other words, it does the exact opposite of the thing you fear that it does. Its entire purpose is to state that the things you described about yourself earlier, such as being a tomboy, are separate from gender identity and biological sex. That being a tomboy, or having interests that are stereotypically gendered, DO NOT make you that gender.
Regarding gender roles, how do you respond to the current zeitgeist that asks if gender nonconforming women in literature and film are in fact trans? For example, Jo March in Little Women, and Mulan.
Those can be interesting conversations even if the answer at the end is "they're still cisgender". Cisgender people have been writing gender into stories for a long time, and a lot of those stories do end up have themes very relatable for trans people. Relooking at media through a queer lens is not harmful.