Upper elementary narrative nonfiction picture book, what to consider before querying?

Hi! I’m drafting an upper elementary narrative nonfiction picture book about William Lloyd Garrison, whose writing was widely read in the years leading up to the Civil War.

The book stays focused on one turning point, not his full life. Early on, Garrison condemns slavery, but insists it will end gradually through careful persuasion and slow political change. His tone is controlled, and his arguments are “reasonable” to other white readers.

Then he starts reading Black abolitionist writers. Their words are urgent and specific about what is happening. Garrison can’t defend his gradual stance anymore, and he changes what he is willing to say publicly. He begins calling for immediate abolition, without compromise or delay.

That decision brings consequences. Friends turn away. Crowds threaten him. His work is attacked. The book frames his shift as listening, not leadership, and keeps Black voices as the force that drives the change. Abolition happens, but the ending makes clear that abolition was not the end of injustice.

I’m aiming for the same upper elementary narrative nonfiction space as Unspeakable, The Power of Her Pen, and Ida B. Wells: Voice of Truth.

A bit about me: I’m a former journalist and educator, and I was a [state award winner of the year]. I’m planning to pursue traditional publishing and am not interested in self-publishing or hiring an illustrator.

I’d love a gut check from people who know this lane. If you were evaluating a manuscript like this, what would you be watching for at this stage? What tends to make projects like this click, and what tends to make them stall?

Many thanks!