This is not accurate.
The timeframe is not wrong; it is true that the concept of the modern police, at least in the US, was largely based on the Peelian model created in London in the 1820s. But saying it evolved from "warehouse guards and slave patrols" is ahistorical. Most modern police forces modeled after London's Metropolitan Police replaced night watch systems that have been around for literally all of recorded history.
I'm not saying the night watches didn't evolve into police departments, I'm saying the night watches were co-opted prior to them becoming uniformed departments.
And slave patrols led directly into being police departments in some parts of the US. I do not claim that's in the history of all depts, but across the south there are many cases of patrols becoming formalized into police departments.
One of their predecessor organisations was the Bow Street Runners which was set up by magistrates with the aim of providing a less corrupt system than that of "thief takers" and a more professional one than parish constables.