It gets expensive after that. One needs to figure out which areas the family lived in and when, and peruse old wills, estates, tax, sales, and other records in search of any names and ages that might have been written down. It takes learning about the whites in the area. Eats the soul.
Genealogy absolutely can be expensive. I can't recommend familysearch.org enough. It's free because it's part of the Mormon ministry. I've had an account for years, and they have never been evangelical about their faith. There are loads of the docs you mentioned available for free.
What I mean by expensive is that the kinds of records that Black People have to seek out have not been digitised. They lie dusty on shelves buried in the bowels of libraries, courthouses, attics of old mansions. One needs to afford transportation, hotel, and sometimes entrance fees. Food, laundry.
One also needs the knowledge of where it is safe to lodge overnights, access restrooms, and procure vittles.
I am a white. I have been able to trace some lines of my tree to the Renaissance and Medieval Eras using FamilySearch dot org. That sort of privilege does not extend to Black People.
It true that only a fraction of genealogical records are digitized. Still best to start with what is free and online.
I’ve paid to have military records searched out and digitised in the hopes that a disability report might mention an ancestor. I have tiny volumes listing Black names in wills. I have thought about the specialized databases that aren’t covered by Ancestry or FamilySearch.
Did you go through the Freeman's Bureau records?