But these numbers pale beside those who escaped in Virginia northward, and whenever Yankee regiments were at all close, there was an exodus to Union lines.
I don't know what history you're using, but I do know that the Richmond Enquirer reported on 3/23/65 that
"The appearance of the battalion of colored troops on the Square, yesterday afternoon, attracted thousands of our citizens to the spot, all eager to catch a glimpse of the sable soldiers. The bearing of the negroes elicited universal commendation. While on the Square, they went through the manual of arms in a manner which would have done credit to veteran soldiers"
Further, Confederate leadership was terrified of arming them, even when individual commanders at times thought it the only alternative.
That is only partially true. Some confederate leaders opposed arming them until 1865. In other cases states such as Tennessee passed laws allowing blacks to be armed in the state militias as early as 1861.
But these numbers pale beside those who escaped in Virginia northward, and whenever Yankee regiments were at all close, there was an exodus to Union lines.
Whether they do or not, it does not alter the fact that there were blacks in the confederate armies including blacks that were armed and even some who saw combat.