It seems that, at least during my education in middle and high school, there was minimal mention of Malcolm X in my history classes and when he was mentioned his role seemed to be heavily underplayed. Is this more due to MLK's dominance of the civil rights movement? Thank you.
I think any answer to this question would be purely an opinion, which makes it impossible to ask in /r/AskHistorians. Unless someone here happens to write history books or know someone that does.
Middle and high school education in the US is not centralized and standardized. Every state makes its own rules for public schools. Private and parochial schools have their own curriculum. Teachers are given certain latitude in terms of what they teach. Therefore, it is not possible for you to extrapolate based on your personal experiences. In order for you to hold this opinion, you would need to look at a study which deals with a large sample of schools.